(1) Oxygen tensions do not affect the larval respiration: the larva respires at a constant rate in 1 to 90% oxygen.
(2) Carbon monoxide inhibits the larval respiration at higher concentrations. Normal oxygen consumption is maintained until the carbon monoxide concentration reaches 90%, but in 95% and 99% carbon monoxide the inhibition ratios are 31% and 55% respectively.
(3) Carbon monoxide inhibition of larval respiration is photo-sensitive. In 95% carbon monoxide the respiration is considerably inhibited in dark while it is not affected in light.
(4) On the basis of this and other data, it is imagined that cytochrome oxidase functions as a principal terminal oxidase in the respiration of Bombyx larva.

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1. The effects of oxygen tensions and carbon monoxide on the respiration of silkworm pupa (Bombyx mori L.) were studied.
2. In the cases of 1 and 7 days old pupae, normal oxygen consumptions were maintained until the oxygen tensions reached 10%, but in 5% and 1% oxygen tensions the respiratory rates were respectively 78% and 54% of the initial level.
3. Throughout the pural stage the respiration of silkworm pupa was considerably inhibited by carbon monoxide and the inhibition was photoreversible.
4. On the basis of this and other data, it was imagined that almost throughout the pupal stage cytochrome oxidase functioned as a principal terminal oxidase in the respiration of Bombyx pupa.

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Effects of calcium cyanamide and its derivatives on the budding of the mulberry-tree, the shoot-top and leaves of which had been removed, were investigated. The results obtained were as follows:
1) It was found that spraying of the supernatant of 5% calcium cyanamide solution and 0.05-2.0% cyanamide solution were clearly effectual on acceleration of sprouting. The most effective concentration of cyanamide solution was 0.5-2.0%.
2) It was uncertain that 0.05-1.0% dicyandiamide solution and 0.05-2.0% guanidine carbonate solution were effective.
3) 0.05-2.0% thiourea and 0.1-5.0% urea solutions were slightly effective on the acceleration, but the action of these groups seemed to differ from that of calcium cyanamide.

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Experiments have been made in regard to expansion and contraction of the silkgland wall after the 4th stage.
If one part of the silkgland is cut off and let alone for a short time in the physiological salt solution, the liquid silk in the cut part comes out gradually from the cut. And at the same time the gland wall is apt to contract in general. Sometimes, it may happen to the contrary depending on the position of the silkgland, but the degree of expansion is extremely small in comparison with that of contraction (Figs. 1-5).
The expanding of the silkgland wall in the blood of the silkworm and the physiological salt solution is due to swelling of the liquid silk or gland cell, and on the contrary, its contracting seems to be attributed to the following reason; that the gland cell, which so far had been expanding according to reserving of the liquid silk in the gland cavity, is getting back to its former position at the same time when the liquid silk comes out.
The expassion is larger in the direction of vertical to the cross section than in that of circumference and the contraction is larger in the direction of circumference than in that vertical to that cross section, and it is due to the difference of tensile stress in the two directions (Figs. 1-5).
The degree of expansion and contraction is not the same depending on the period of larval development, on the position of the silkgland, on the liquid in which the experiment was made (the blood of silkworm or the physiological salt solution), the silkworm strain, the sexual differerence of silkworm, and so on; and it was discussed for reasons of them (Table 1).
A comparatively big contraction in the direction of circumference of the anterior section at the middle division on the first day of 4th or 5th stage, seems to have some relations with silk spitting by the moulted larvae (Figs. 1-5).
In regard to the ripened larvae, the degree of contraction of the wall of middle section is proportional to the degree of divisible fibres in the cocoon thread. It seems to be attributed that the degree of divisible fibres in the cocoon thread is proportional to the elasticity of the gland wall or the quantity of the liquid silk stored in the gland cavity (Fig. 6).

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(1) The wave shape of the flow of liquid silk in the silkgland at the middle division of the ripened larvae could be observed for which discussion based upon the hydrodynamical views has been made. The wave mentioned above is different thing with that of so called “plait” which is said to give cause for becoming the divisible fibres (Fig. 1 & 2).
(2) The tensile stress in the silkgland wall seems to be represented as following order of their magnitude: middle section of middle division > posterior section of middle division > anterior section of middle division > posterior division > anterior division (Table 1).
(3) It is presumable that the pressure of liquid silk in the gland cavity, which has raised to some degree, becomes an incentive of spitting the silk out. Explanation for the longitudinal splitting of silkgland wall at middle division, which is caused by the stop of spitting the silk out, is able from points of the pressure of liquid silk, the elasticity of gland wall and the tensile stress of gland wall.
(4) The degree of elasticity of silkgland wall and the shape of gland cavity at the anterior and posterior sections of middle division seem to be convenient for the liquid silk to enter from posterior division into middle division and to move from middle division to anterior division together with spitting the silk out (Fig. 3).
(5) The internal friction of liquid silk and the friction of liquid silk against the silkgland wall has been discussed.

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The present report was dealt with the results of the experimental researches to find out the biological significances of the rapid increase in the quantity of waxy substance over the skin surface of Bombyx at the period just before pupation. The results obtained are as follows:
1. If the skin surface of the larvae is abraded by rubbing it lightly with fine alumina dust and is deprived of the epicuticular wax in the late larval and prepupal period, the percentage of the larvae that fail to pupate increases. The phenomenon is especially remakable, when the treatment is done during the period in which the wax shows a rapid increase.
2. However, the failure of the ecdysis does not take place, if the abraded portion of the integument is smeared with a thin layer of vaseline.
3. The increased rate of transpiration from the abraded animals continues longly to their drying up followed by death, when they are treated in the period during which the pupation fails by the abrasion.
4. The solution of the old skin in moulting fluid was found to be incomplete at the portion at which it had been partially unshed off.
5. The epicular wax in the prepupa just befor the pupation differ in both quality and quantity from race to race. There is a clear tendency that the occurrence of pupae which are incapable of shed off their old larval skin is frequent in such races as that possess the waxy substance in smaller quantity at that period.
6. If the larvae spin their cocoons at higher temperatures, the epicuticular wax increases in amount during the prepupal period, and the number of animals incapable of the transformation into the complete pupae becomes smaller as compared with those spinning at lower temperatures.
7. Thus it is of little doubt that the abrupt-increase of the amount of the superficial wax is a phenomenon highly necessary for the completion of the ecdysis. At present, its mechanism is not completely clear, but it may safely be concluded at least that the responsibility of the wax for the waterproofing of the cuticle is greater during the period preparing for the pupation as compared with the other period.

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This study was undertaken in order to clarify the effect in the body fluid component, especially the total reducing substances (blood sugar), at the 5th instar of the silkworm whenthe shaded mulberry leaves were fed during the 1st. and 2nd. instar.(Materials: Shi No.122×Nichi No.122 and Shi No.155×Nich No.122)
(1) In the silkworms of spring, early autumn and late autumn rearings, the feeding of the shaded leaves gave no recognizable effect on the total reducing substances content.
(2) In general, the total reducing substances content in the body fluid at the 5th instar of the silkworm are nearly the same for male and female, but the content is variable in different rearing seasons. In the early autumn and late autumn seasons, the value is higher than in the spring rearing. In the diseased silkworms (flacherie) it has a tendency to be decreased.

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The time of ecdysis was observed under the constant condition of light and temperature using eight different strains of the silkworm, Bombyx mori. As represented graphically in Fig. 1 and 2, the frequency of the time of 2nd moult does not show normal distribution but bimodality is some strains, which grow rapidly and have broad range of individual variation in their development.
The time of ecdysis in a day retards from evening to midnight and is accerelated from downing to noon, and it shows daily rhythmicity under the constant condition of environment. Therefore, it seems that it is not governed by outer environmental factors but is regulated autonomically. The degree of this autonomy is distinct in the 1st or 2nd moult, and becomes less evident in the 3rd moult, which is considered as a critical period physiologically.

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In this experiment the specific gravity was studied of the blood of silkworms which were starved from the 5th day of the last larval instar to the 4th day of the adult insect.
Even in the case of starvation from the 5th day of the 5th larval instar, the larvae were able to spin cocoon, and to pupate and to become adult owing to the nutrient preserved in the body during the former 4th days of the 5th instar. In this case the specific gravity of the blood began to fall at once by fasting while the specific gravity of the blood in the normal state was on the route of ascension*. At the time corresponding to the voraceous period of normal insect, the specific gravity of the blood rose a little and then descended gradually. The variation from the prepupal stage to the end of the pupal stage showed almost the same tendency as those of the unstarved one but the values were always lower.
The specific gravity of the blood in adult was almost the same in both cases starved and unstarved.

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The author has ascertained the manifestation of the phosphorylase activity during the embryonic development in the silkworm by determining the liberated P, the disappeared 10'P, that is hydrolyzable P compounds in N HCl at 100°C for 10 minutes, and the glucose formed in the experimental conditions.
The activity showed such varieties during the incubation at 25°C as following: After the hydrochloric acid treatment for the artificial hatching preceding the incubation, it declined and was kept at constant low level until around the blastokinesis, followed with rapid arise and reaching the maximum at the period just before the head pigmentation and then decreasing again. Since this tendency was antagonistic against that of the glycogen content, the author assumed that phosphorylase played an active role in the glycogen metabolism in this insect.
Two forms of glycogen, free and fixed, were also detected as shown by KEMP et al (10) in mammalian tissues. Phosphorylase may be concerned in the free glycogen, because the free glycogen varies in its content in proportion with change in the enzyme activity, whilest the fixed glycogen does not.

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Silkworm pupae were dried at 80-90°C and ground. After ether extraction for 30 hours, the residue was shaken with 95 per cent methanol at room temperature for 30 minutes. The mixture was centrifuged and the supernatant was filtered. The precipitate was extracted with 95 per cent methanol with repetition of extraction with methanol. Methanol was distilled off and the residue was dried on the water bath. About 30 g of methanol extracts was obtained from 200g of ether extracted pupae through 7 times of extraction.
By addition of a small amount of glacial acetic acid to 13.5 g of methanol extract, needle crystals were obtained, but not with the use of 90 per cent acetic acid. The crystals were separated from the mother-liquor by centrifugation and letting the supernatant solution to stand overnight at 5°C. The crystals were washed with glacial acetic acid, acetone, and ether and were recrystallized from distilled water (Fig. 1). The yield was 31 mg.
Ultraviolet spectrum of the crystals (Fig. 2) is the same as tyrosine (max. 223 and 275mμ, min. 245 mμ). The Rf value corresponded to that of tyrosine and one spot was with the mixture of the crystals and tyrosine. The melting point was 290-295°C (with decomposition) and it did not decrease when the crystals and tyrosine were mixed.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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Seasonal changes in contents of reducing sugars were studied micro-chemically in the main stems of six years old Quercus trees and in their branches grown for rearing wild silkworms. The quantity of the sugars was found muchin the dark, in the pith ray in wood, and in the pith, and it was scanty in the xylem except the pith ray throughout the year. In winter the sugar contents increased greatly in accordance with the decreases of the starch content. The sugars increased in quantity first in the pith and then in the pith ray, and last they were concentrated in the primary cortex in mid-winter. The increase in the sugar contents in winter can be considered as the indication of increasing coldhardiness of the plant. The sugar contents decreased in spring during the budding-time and they showed themselves to be of value generally during the growing season than in winter, showing increases in the time of growth at the maximum rate and decreases in the time of growth at the law rate.
It was worthy of our notice that the contents of both the sugars and the starch decreased obviously in the stems and in the branches in late September, before which the temperature of the air near the ground was higher than that of the underground, after which the former temperature was lower than the latter.

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[in Japanese]

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