[in Japanese]

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The present experiments were carried but in order to make clear the relation between the strains of mulberry trees and the period of appearance of such sugars as maltose, raffinose, sucrose, fructose and glucose and also their content in the shoots of each strain in autumn and winter using 32 varieties of mulberry trees.
The results of these experiments may be summarized as follows:
(1) From the viewpoint of the difference of the content of maltose in the shoot, mulberry trees may be classified into 4 groups: one group which has much maltose for longer period, is proof against the cold, belonging to the hardy plant strain; theother 2 groups which have little maltose for the whole period and also much maltose for a little while, are easily affected by the cold, belonging to the soft plant strain; the remained group which belongs neither to these both groups is in middle in all properties.
(2) From the viewpoint of the differences periods of the appearance of raffinose and stachyose in the shoot, mulberry trees are classified into 9 groups. These groups in which the above mentioned sugars appear in the earlier period were considered to stop their growth in earlier time.
(3) The content of sucrose in the shoot is little in the earlier time of autumn, but it increases gradually with the lapse of the time of the growth. In some varieties of mulberry trees, the content of fructose in their shoots decrease temporarily around the 8th of October. In general, the strains in which these sugars appear in their shoots in earlier period have tendency to become early into the winter form.
(4) From the viewpoint of the difference of the peried of appearance and disappearance of glucose in the shoot and also from the fluctuation of its content, it is difficult to group the varieties of mulberry trees.

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During the operation of artificial pollination by means of routine method in mulberry trees, it is difficult to keep out another pollen-grains naturally pollinated. The operation usually practiced is troublesome and is not suitable under windy weather. We have succeeded to design the pollen-gun, a kind of pollinator and to cover up the weak points of usual operation above mentioned.
Results obtained from the field-experiments were as follows: 1) differences in fertilities of the seeds produced through both operations of pollination were not significant, 2) and we have succeeced to reduce the operation time of pollination by about one-half.

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Bezuglich des hämopoetischen Gewebes der Insektenembryonen kommen nach den zusammenfassenden Darstellungen von HIRSCHLER ('24-'27), JOHANNSEN und BUTT ('41), MUNSON ('53), POULSON ('50), WEBER ('54) und WIGGLESWORTH ('50) verschiedene histologische Elemente in Frage. Die in 1902 veröffentlichte TOYAMA sche Ansicht, welche den Subosophagealkorper der Seidenraupe als blutzellenerzeugend auffasste, konnte in vielerlei Hinsichten in unserem Lande bis jetzt nicht festgestellt werden. Nach IKEDA ('13) ist der Subosophagealkorper ektodermaler Herkunft, wahrend auch, die Hamopoese im Mesoderm stattfindet. IWASAKI ('32) berichtete, dass die zwischen den Keimstreifen und den Stomodautn frei eingewanderten Zellen, die von TOYAMA als Blutzellen angesehen wurden, nicht zum Subösophagealkörper, sondern zum vorderen der polaren Zellenhaufen gehoren, welch sich spdter in der embryonalen Entwicklungsvorgänge vom Keimstreifen trennt.
Nach meinen Beobachtungen entsteht der Subösophagealkörper aus dem postoralen Teil des unteren Blattes, so dass er dem Mesoderm angehorend ist ('55), dagegen letzt degenerieren sich die aus der polaren Zellenhaufen gebildeten Zellen ('54). Es lasst sich nahmlich in einem friiheren Entwicklungsstadium vom langgestreckten Embryo eine Reihe von Zellen an den beiden ventrolateralen Randpartien des Sübosophagealkörpers deutlich erkennen. Bald werden als dann an dem distalen Teil dieser Zellenreihe freie Zellen, Urblutzellen, ersichtlich (Abb. 1) und sie einwandern allmahlich ins Dotter. Im Laufe der weiteren Entwicklung teilen sich diese Zellen mitotisch aus dem Subösophagealkörper; später beim ausgebildeten Embryonalköper, in welchem der Subösophagealkörper als Syncytium zu betrachten ist, kann dieses blutzellenbildende Wachstum nicht mehr erkannt werden, und es scheint mir, dass noch anderes mesodermale Gewebe hamopoetisch wichtige Rolle spielt.
Für die Feststellung der Einzelheiten der Stammesdifferenzierung der Blutzellen sind weitere eingehendere Untersuchungen nötig.

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Since little is known about the enzymic oxidation of L-amino acid in the silkworm egg, we have tried to make clear this problem by using L-alanine and L-glutamic acid as substrates.
The results obtained are as follows:
1) In the presence of L-amino acid, NH₃ output by the enzyme solution prepared from silkworm eggs increased with O₂ uptake by the enzyme solution. The molar ratio of NH₃ output: O₂ uptake was nearly 2: 1. This fact suggests that the amino acids are desaminated oxidatively by an oxidase or an oxidase system in the silkworm egg.
2) As it was not until about 1/500 M of potassium cyanide that the activity of the oxidase was almost completely inhibited, the enzyme seems to have relatively strong resistance to the cyanide.
3) The activity of L-amino acid oxidase in the silkworm egg increased gradually till the middle of incubation, and thereafter it decreased towards the hatching. From this, it may be postulated that the oxidase is connected physiologically with the consumption of the yolk.

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It has been observed in the present work that O₂ uptake by the white rot silkworm eggs is-decreased strikingly in comparison with that by the normal eggs at the end of incubation. For elucidating the fact, we have comparatively investigated the changes in the activities of some respiratory enzymes such as succinic and malic dehydrogenases and L-amino acid oxidases in the homogenate of both normal and white rot eggs during the incubation. The results obtained are as follows:
1) Each activity of succinic and malic dehydrogenases in a group treated to be produced 60-63 per cent white rot eggs was in almost the same extent as that in the normal eggs at the beginning of incubation, whilst at the end of incubation it declined to about 2/3-1/2 times that in the latter.
2) The activity of L-amino acid oxidase in a group of 60-70 per cent white rot eggs decreased remarkably in comparison with that in the normal eggs at the end of incubation.
3) O₂uptake by the homogenate of normal eggs was much enhanced in the presence of malic acid, while O₂uptake by that of white rot eggs in the same condition was almost unchanged.
4) From these results, it may be considered that the remarkable decline of O₂ uptake by white rot eggs is due, at least in part, to the weakening of the activity of oxidases in them rather than dehydrogenases.

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In special attempt to find the changes in the cuticular contributions to the water economy of silkworm during its development, some measurements and histological observations were made on the physico-chemical and microscopical properties of cuticle, its ether extractives, and epicuticular wax with the changes of the weight and surface of the body during the period extending from 4th larval instar to the pupation ecdysis. The results obtained are as follows:
1. There is a rapid loss in the weight of the body as well as its surface area during the prepupal period in contrast to a rapid increase in the 4th and 5th larval instars.
2. A large number of wrinkles appears all over the surface of the integument of the prepupa, especially profoundly on each intersegmental membrane. They increase in number and depth as the development proceeds. Histological observations show that these wrinkles are the invaginations of epi- and exocuticle into the part of endocuticle.
3. The cuticle increases in thickness during the 5th instar of the larva, more quickly in the prepupal period.
4. The amount of ether extractives ot the cuticle to the unit quantity of the cuticle as well as to the unit area of body surface increases from the 5th instar of the larva to after mounting of the larva.
5. The quantities of epicuticular wax, absolute, to the unit amount of the cuticle, and to the unit body surface do not change so markedly during the 5th larval instar, while they increase with the development of the prepupa to the conspicuous highest values just before pupal molting.
6. The melting points of the epicuticular wax are higher in the prepupal than in the larval period. They show a progressive elevation in the former, reaching the highest value in the late prepupa.
7. All the facts described above seem to tell a series of adaptations for the higher necessity for the restriction of water loss through the integument of the prepupa which do not take any amount of water from environment as compared to the larva to whom water is sufficiently supplied from mulberry leaves.
8. The same facts are also seen in the larva during the period of ecdysis during which the worm must be very sensitive to the transpiration.
9. It was proved that the exuviae from pupation ecdysis (=last larval ecdysis) consists mainly of the epicuticle. Consequently the wax obtained from the exuviae may be called the pure epicuticular wax.
10. The epicuticular wax from the pupal exuviae has almost the same physico-chemical properties as the one obtained by extraction from the living cuticle of the larva.
11. By abrading the living larva with fine alumina dusts or by weaping the integument with chloroform, we can prepare some amount of epicuticular wax, the properties of which are almost the same as the one obtained by extraction from the exuviae of the last larval instar or from the living cuticle.

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The present experiments were carried out in order to isolate the components of proteins contained in the body fluid of the fifth instar of Bombyx mori L, and to identify the sorts of their proteins, by means of salting out and electrophoresis.
The experimental results may be summarized as follows:
(1) From the fluid above mentioned, seven protein fractions were obtained by salting out with use of (NH₄) ₂SO₄.
(2) Two fractions were successfully obtained in the comparatively pure state, considering from the formation of the single boundary by electrophoresis and from their electrophoretic behaviours and solubilities; the one showed the albumin nature and the other globulin one.
(3) These two proteins were hydrolized respectively, and several amino acids in these hydrolysates were estimated, resulting in a remarkable difference between these two proteins in the content of amino acids.

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In this preliminary report, the experimental process, the result and the discussion concerning the studies on the proteins of the cuticles of silkworms are described. The experimental result and discussion may be summarized as follows:
(1) Three protein fractions were separated respectively from larval and pupal cuticles and also from cast skins of silkworms. These fractions are:(a) water soluble;(b) water insol. but N-NaOH soluble and (c) insoluble in both water and N-NaOH.
(2) With each protein of these fractions, acid hydrolysis was practiced respectively. Amino acids in these hydrolysates were found to be similar with each other in their kinds, on the view-point of chromatography.
(3) The percentage of N contained in the N-NaOH sol. protein is lower to the extent of about 2% as compared with that of the water sol. protein, through the various cuticles.
(4) Free amino groups in each protein of these fractions were testified by means of the D. N. P.-and the P. T. C.-method, the result of which devoting a remarkable decrease of amino groups in the N-NaOH sol. fraction.
(5) From the above mentioned experimental results, the water sol. protein is deduced to be converted into the water insol. one by combining with some other substances at its free amino group. This fact is considered to have connection with the phenomena of hardening and darkening of the cuticle.

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1. Vitamin B₂ concentration in the blood increased gradually during the period of pupation. That of the female pupae reached maximum at the fifth-or sixth-day after pupation at 23°C, and decreased in three or four days after that period. In the male pupae, however, no peak at the fifth-or sixth-day was observable.
2. The VB₂concentration in the blood of the female pupae from the second- to the seventh day after pupation was higher than those of males.
3. The VB₂concentration in the blood of the female pupae in which both ovaries had been removed out during the fifth larval stage increased grandually, and in the ovariectomized moths they were four times higher than those of the normal female moths.
4. The VB₂contents in the eggs laid by the moth, one of whose ovaries had removed out during the fifth larval stage, were higher than those of normal one. The fimilar relations between the normal and the ovariectomized were observable in the measuring of the weight and the number of eggs.
5. The VB₂contents in the ovaries increased markedly in the middle pupal stage, and this phenomenon is resemble the mode of the increase of the weight of the ovaries.
6. From these results, it is concluded that considerable amounts of VB2 in the blood are transfered into the ovaries, and this transference is remarkable in the middle pupal stage.
7. There was no marked difference in VB₂concentration between the blood of the male pupae which had the implanted ovaries and those of the normal male pupae. However, from the result of measuring the VB₂ contents of the ovary implanted into the male body, it was ascertained that VB₂was transmitted into the implanted ovary.

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Usingod-translucent and normalBombyx, vitamin B2 in the blood of larvae and in the eggs was measured. The results obtained were as follows:
1. During the fifth larval stage, there was no marked difference of the vitamin B2concentrations in the blood between od and+.
2. During the pupal stage, vitamin B2 concentrations in the blood of+were higher than those of od, but no difference was observed concerning the modes of changes in the vitamin B2concentration between both strains.
3. Vitrmin B₂contents in the egge laid by normal moth were greater than those by od moth in both the receiprocal crossings between normal and od.
4. From the results of present and previous experiments, it seems that the greater part of vitamin B₂in the egg is transmitted from the mother moth.

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Japanese race No.122 looks pale red during the 5th instar especially in its earlier stage owing to the reddish brown pigments in the skin. The present study deals with the data concerning the properties of this pigment and the mechanism of its pigment formation.
1. This pigment appears on the 4th day of the 4th instar, and the colour tone is deeper in the 1st to the 3rd day of the 5th instar, but, gradually, becomes weak after the 4th day. It is probable that the pigment is mainly formed during the 4th moulting period, and, thereafter, the pigment formation is ceased or become out of proportion to the rapid development of the silkworm body resulting in the sparse distribution of the pigment.
2. On the histological observation, this pigment is localized in the form of reddish brown pigment granules in the lower part of the epidermis contrary to the case of the deposition of red pigment at the marking of eye spot (Fig. 1).
3. The pigment is extracted and examination is done on the chemical natures by the method prescribed in the previous paper. The Rf value (solvent: formic acid) of this pigment is 0. 82 (Tabl. 1) and the absorption curve has a maximum at 450-460 mμ(Fig.2).
The orange colour of the pigment solution changes yellow by oxidation with H₂O₂, and turns pink by reduction with Na₂S₂O₄.
Although a slight differences on the colour tone and the pigment distribution may exist, the chemical properties are closely similar to chrome-I derived from tryptophane.
4. 3-hydroxykynurenine is accumulated in the integument of Jap. No.122 from the 3rd day of the 4th instar to the 4th moulting period. From this it is likely that the formation of this pigment is closely connected with the accumulation of 3-hydroxykynurenine in the integument.

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Copper were detected in the blood of several insects by MUTTKOWSKI (1921) and in the blood of silkworm larvae by YAMAZAKI et al and it is suggested that copper in the blood may be the one contained in hemocyanin. But their records are not so precise that the present author does not agree with their suggestions because such copper enzymes as tyrosinase are found always in the blood of insects.
The author estimated copper in the blood of the silkworm larva by means of WARBURG manometric method and tried to know its physiological significance and got the following conclusions.
1) Copper is contained in the blood, but its amount is far smaller than that of animals which have hemocyanins in their blood.
2) The copper content in the blood fluctuates daily in the 5th instar: that is, the content is small immediately after the moulting and increases after the feeding, but it decreases on the 2 nd day and then increases again and reaches to the maximum on the 4 th day. After that it decreases gradually and becomes to the minimum in the matured lava, as shown in Table 3.
3) The copper contents are the same both in the fresh and incinerated blood, as shown in Table 3.
4) If the amounts of copper in both the mutantsp^sandp⁺are compared each other in the same batch, they are larger in ps than inp⁺
5) The fluctuation of copper contents in the blood mentioned above coincids with that of tyrosinase activity (ARUGA et al, 1952).p^scontains more amount of copper and according to ARUGA, is stronger in tyrosinase activity thanp⁺. These facts suggest that most of coppers in the blood may be the one contained in tyrosinase so far this experiment concerned. On the other hand, such copper tightly united with a compound as in hemocyanin is said to be difficult to estimate unless the blood is incinerated. Whilest, copper content in the blood is the same both in the fresh and the incinerated ones. This fact suggests that hemocyanins are not contained in the blood. And if hemocyanins are contained in the blood, the fluctuation of copper content, in the blood shall be parallel to that of blood gases contents (IWANARI, 1952) Both figures, however, are quite different and the presence of hemocyanins in the blood is also doubtful from this standpoint of view.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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The authors studied on the assimilation of water in silkworm-larva estimating the specific gravity of blood.
1) When the larva feeds on mulberry leaves moistened with water, the specific gravity of the blood falls down rapidly up to 0.5 hours after the time of taking water in4th stage (Fig. 1) and 0.5-1.5 hours in 5th stage (Figs. 2-3).
2) In the case of 5th stage larva, the eaten mulberry slices reach the posterior parts of 3rd-5th segments which correspond to the anterior to the middle parts of mid-intestine in 20 minutes and the posterior, parts of 4th-6th segments which correspond to the middle part of mid-intestine in 40 minutes (Table 4).
In the case of 5th stage larva, the slices reach the posterior parts of 2nd-4th segments in 20 minutes and the posterior parts of 3rd-5th segments in 40 minutes which correspond to the anterior to the middle parts of mid-intestine each. Accordingly the water taken from the mouth can be absorbed in the haemocoel through the intestinal wall in 20 minutes and the specific gravity of the blood will be affected.
3) Although the specific gravity of the blood fallen down by taking water risesby feeding on normal leaves, the complete restoration of the density of the blood is so slow as it takes about 4 days. it seems that the regulation ability of water content inthe blood is not so active in this insect.

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The author has performed experimental, morphological and physiological studies on the colouring phenomenon of the body surface of the newly moulted larvae of some strains (brown spotted larva, E 18 and N115 etc.) which coloured on the surface of epicuticles. The results obtained are as follows:
When the secretory substance from the dermal glands of alveolar type is mixed with that from the granular one the coloration on the body surface appears in the newly moulted larvae. This was ascertained at the surface of the new cuticle underlying the old one by means of ligature experiments at a boader of two types, i. e., between the 6th and 7th segments. This fact suggests that chromogen is secreted from one of two types of the glands while enzyme oxidizing the chromogen is from the other.
Especially in both the species, the brown spotted larva and E18, some chracteristic brown spots appear at the openings of the alveolar-type-glands. This fact appears that the forming mechanism of the spots is the same as above-mentioned colouring phenomenon.
Since phenols such as tyrosine, catechol and p-cresol, are oxidized by the secretory substance from the alveolar-type-glands, a phenol oxidase seems to be contained in the secretory substance. Although there is a metabolic path way from phenylalanine to tyrosine as shown by Haldane (1942) in man and by T. Fukuda (1955, unpublished) in Bombyx, the phenomenon which phenylalanine is coloured by the secretory substance is unable to be explaned with the author's experiment. On the contrary, the above-mentioned phenols are not oxidizable by the secretory substance from the granular-type-glands. By this fact, it seems that in the granular-type-glands the enzyme exists in very few, even if it is present, or does not. Phenylalanine is not coloured by the secretory substance.

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For the purpose of answering the question that, in Bombyx, the brain is responsible for its imaginal differentiation or not, the author has performed the experimental study on the function of the brain during the young pupal stage.
The Bombyx-pupae of F, hybrid between the races, Chinese No.115 and Japanese No.122, were used as materials at various ages from immediately after pupation till 48 hours after that. Two controls, wounded only in the head and unoperated, were set at the exterpation experiment.
As a result of exterpation of brain, as shown in Table 1, some pupae which do not show any imaginal differentiation appear in females operated within 3 hours after pupation, while in males within 4 hours. In these pupae which were called in term of the eternal one, no imaginal differentiation could be observable even though they were kept at 25°C as long as more than 100 days. These are resemble that in a state of diapause as seen in Secropia. Those, who were operated at under 12 hours old at their pupal age and failed to be eternal-pupal, took more time than the elder ones operated or the controls. In this case, the younger took the more days to become imaginal.
In order to break the eternal state, the author tried another experiment that the fresh brains obtained from the normal pupae under 12 hours old after pupation were reimplanted into the head of the eternal pupa of 55 days old at 20°C after pupation. It resulted in that three eternal pupae became imaginal at 14, 18 and 19 days after the time of implantation. The above results speak for the effect of brain on the imaginal differention should be a hormonal one.
In conclusion, then, it seems that, in Bombyx, the hormone secreted from brain initiates an imaginal differentiation affecting the prothoracic glands and that a critical period for effectivness of the hormone exists within 3 hours after pupation.

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Supernatant (3, 500 rpm for 15 min.) of the silkworm blood was fractionated with ammonium sulfate at 1/3, 1/2, 2/3 saturation, or saturation, and each antigenic titer in the precipitation reaction was 102, 400, however, 3, 200 in the original blood. Heating 1/2 saturated or saturated fraction at 56°C for 60 minutes, the antigenic titer did not decrease.
When the electrophoresis employing veronal buffer (pH 8.6, I=0. 1) was performed on filter paper, it was found that migrating (2-3 bands) and not migrating components were contained in the supernatant of the blood. Judging from the patterns of egg albumin, albumin from blood and albumin from wheat, most migrating component seems to be albumin fraction.
Precipitate with ammonium sulfate at 1/3 saturation, considered to be globulin, did not migrate from the starting line and contained small amount of albumin. But in the fraction with ammonium sulfate at 1/2 saturation contained both albumin and globulin, while in the 2/3 saturation or saturation, the amount of albumin increased more than in the fraction at lower saturation.
The ratio of albumin/globulin in the course of development from the larval to pupal stage, there seems to be two fractions in the pupal blood as migrating bands and its color densities were strong. The change was also shown in the migrating bands of the jaundicediseased blood as compared with the normal larval blood. The pattern of the polyhedra (dissolved in 0, 5 per cent Na₂CO₃ and the resulted supernatant was adjusted to pH 8.6) did not migrate.

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The present paper deals with the diminution of the virus activity with increasing time of the ultraviolet irradiation.
Supernatant (3, 500 rpm for 15 min.) of the infected pupal blood was diluted 10^-3 or 10^-3 with distilled water and centrifuged at 3, 500 rpm for 10 minutes. The fluid was prepared in a Petri dish at the depth of 2-3 mm, being exposed to ultraviolet radiation from Matsuda GL-15 type ultraviolet lamp with about 95 per cent of its ultraviolet output at a wave length of Å and tape distance from the lamp to Petri dish was 40 cm. The sample was gently agitated every 5 minutes. After the ultraviolet irradiation, decimal dilution was performed immediately and 0. 005 ml of the virus solution was injected into pupae. LD₅₀ was calculated after REED and MUENCH.
Results obtained are shown in Fig. 1. There is a linear relationship^between LD50 and the irradiation period accords with the mode of the inactivation of other viruses, and when the higher diluted virus solution is used, the inclination of the line becomes steeper. Silkworm jaundice virus seems to be inactivated by the absorption of one ultraviolet quantum as in the inactivation of bacterial virus.
The temperature in these experiments was 15-20°C and its increase owing to the irradiation was less than 2°C after 60 minutes.

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Generally it has been believed that the aqueous extracts of pure silk do not show the polarographic-protein-wave.
The authors, however, have observed the small polarographic-protein-wave with colloidalsolution of sericine which is prepared from cocoon shells of Bombyx mori and a distinctcystine wave with sericine hydrolysates. Fibroin hydrolysates also show a distinct cystine wave.
It was found that cocoon fibres contained cystine and sericine B contained a great dealof cystine comparing with sericine A.
The reality of these cystines are proved polarographically by means of addition of purecystine and treatment of hydrogen peroxide, and cystine contents in these hydrolysates couldbe determined with polarographic method.

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The analyical methods heretofore in use for detection and determination of inorganic elements contained in the water for filature considered to have much room for improvement.From this viewpoint, we intended to apply the analytical method of spectrophotornetry, instead of the existing ones. As the result of this application, we found that the formermethod is much more suitable for this purpose than the latter ones. So we denote in thispaper the directions for the use of this method, especially in details the photographingconditions and how to make the calibration curves and, illustrate them in addition byexamples.

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The contents of starch grains in the main stems and branches of six years old Quercus trees, the feed of wild silkworm, were studied histochemically throughout a year at Ariakedistrict, Naganoken, Japan. The result obtained were as follows:
1) Seasonal changes in the contents of starch grains throughout a year are the samein stems and branches in spite of their ages. The mode of change in starch contents inthe terminal of each stem and branch was more obvious than that in the proximal ends.
2) There were two periods which showed the maximum values of starch contents ineach part of them; the one was in just before shooting and the other is in that of autumunalcoloring of the leaves. They were more obvious in the latter period than in the former.There were also two periods of the minimum values of starch contents; the one was inthat of rapid growing of shoots and the other is in mid-winter. In the former period, almostall of the starch grains in the wood disappeared, while in the latter period, almost all ofthem in the bark and wood were lost.
3) The increase of fat contents in accordance with the decrease of starch in wintercould not be observed, but an increase in the sugar contents could be seen.
4) When they were accumulated in stem, the starch grains appeared at first in theouter side of cortex and then gradually entered into inside of the stern. Whilest, whenthey were lost, their decrease were observed at the bark at first and then at the inside ofcortex. In the wood part, their increase and decrease occured at the same time throughthe tissue.
5) It was found that in stems and branches of the Quercus trees a special tissue forreserving starch grains were formed between periderm and primary cortex. The tissueswere formed from the middle of September till the beginning of October. In autumn a lotof starch grains accumulated in the tissues but in winter they disappeared from them.

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[in Japanese]

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