During three years from 1956 to 1958, intea-and inter-breed matings, involving White Leghorns (WL) and Barred Plymouth Rocks (BPR), were conducted. Average coefficients of inbreeding were 3.4 and 9.2% in WL and BPR, respectively. Data were collected from 762 purebred and 586 crossbred females originating from 16 sires and 141 dams of WL and 16 sires and 119 dams of BPR. Mating systems were such that the purebreds and crossbreds were half-sisters. Measurements of body weight were taken at 0, 4, 8, 12, and 18 weeks, at the laying of the first egg, and at 48 weeks in adult hood. The means and their standard deviations for all surviving birds are presented in Table 1. The significance of differences between mean weights is given in Table 2. An effect of heterosis appeared definitely at the age of 4 week. The potence ratios (F1-Pm/|P-Pm|) of F1 hybrids were 10.33 and 8.93 in WL_??_×BPR_??_and their reciprocal cross, respectively. Afterwards the body weight of crossbreds approached to midparental values.
The most interesting result is the finding of differences between reciprocal F1 hybrids at the age of 12 and 18 weeks. The "t" tests showed that the BPR_??_×WL_??_gave significantly heavier offspring than the reciprocal cross. Heritability estimates based on variance components for body weight at different age were generally higher than those previously reported for this trait. They were 0.675, 0, 637, 0.455, and 0.637 on an average at six different ages in WL, BPR, WL_??_ BPR_??_, and its reciprocal, respectively. Only additive and no maternal effects for genetic variance, being taken into consideration heritability estimates are provided by hs+d2=hs2=hd2. There are some discrepancies in this study between heritablity estimates from sire and dam components in F1 hybrids at various ages, especially in the range of 4 to 12 weeks. These results suggest that some genes having the effects of dominance and/or epistasis affect growth rate in the crossbreds. The variability, in terms of coefficients of variation (CV), of body weight of purebreds was remarkably higher than that of crossbreds, at the age of 4 to 12 weeks. Judging from the general idea of developmental homeostasis that heterozygotes have more consistency in development than homozygotes, the degree of homeostasis may be provided by CV, as was suggested by other researchers, The results obtained here show, therefore, that a very effective homeostasis is operating on the body growth of F1 hybrids at least from the 4th to 12th week of their development.

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Within-breed and between-breed matings were using 16 sires and 141 dams of White Leghorns (WL) and 16 sires and 119 dams of Barred Plymouth Rocks (BPR). Average coe. JJicients of inbreeding of parental purebreds were 3.4 and 9.2% in WL and BPR, respectively. Mating systems were such that these purebreds and crossbreds were half-sisters. A mortality analysis of data given in a previous report, exclusive of those on the T2 group (kawahara, 1957) and birds which died accidentally, was performed.
Data were collected from 615 purebred and 508 crossbred females. The birds were maintafined, without any conscious culling, up to 120 days after they laid their first egg. Mortality was recorded in two periods, i. e. the growing (up to 18 weeks of age) and the maturhlg (from 18 weeks of age to 120 days after the first egg was laid). Total mortality data with the significance test based on chi-square are summarized in Table 1. The diseases observed at death were classified into ten general types shown in Fig. 1. Statistical analysis of the data gave the follow- ing results.
1) Total mortality in the growing period was 5.7% lower among crossbred chicks than purebreds. This difference was statistically significant at the 1% level. Total mortalitY was 3.2% higher in BPR than in WL (11.5% vs. 8.3%). Mortality among F1 hybrids was l.7% hlgher in BPR_??_×WL_??_ cross than in its reciprocal (4.9% vs. 3.2%). These differences were not statistically significant.
2) Total mortality in the maturing period among F1 hybrid chicks was high than that among purebreds (11.8% in WL, 20.9% in BPR, 15.6% in WL _??_×BPR_??_, and 21.5% in BPR_??_ ×WL_??_), and was only a little higher than that in the maternal purebred half-sister group. The differences in total mortality between the purebreds and the maternal crossbreds however were not statistically significant.
3) It is obvious that the main cause of difference in total mortality between the growing and the maturing period was loss from visceral-form leucosis. Fig. 1 shows that a larger part of the difference in mortality between various groups was also due to leucosis. Deaths from leucosis among hybrids were actually more than those among their purebred maternal half-sisters (2.5% in WL, 9.9% in BPR, 6.4 % in WL_??_×BPR_??_, and 11.0% in BPR_??_×WL_??_). In this case mortality from this disease was as high as 8.5% in the crossbreds and 5.5% in the purebreds, the difference apProaching the significance level (x2=3.79, .10>P> .05). The difference of 6.2% in mortality between the maternal groups (4.2% in the WL maternal groups and 10.4% in the BPR maternal groups) was statistica11y significant at the 1% level.
Resistance and susceptibility to visceral-form leucosis were controlled, in larger part, by maternal factors and genotypes.

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A study was made to find out a new method for the determination of feed digestibility in poultry. Two instruments, a rectal and a cloacal tubes were devised by the authors for the collection of feces.
The authors could easily separate the feces from the urine by using either tube, and calculate the digestibility of feed by employing the indicator method in which chromic oxide acted as indicator. Of the two tubes, the cloacal tube was found to be more convenient and more easily applicable to any chicken for digestion study.
The superiority of this method using one of these tubes was discussed and compared with the total collection method (method to determine total nitrogenous compounds in the urine) which had also been devised at the same time by the authors for poultry.
In experiment I, the digestibility of a commercial feed was examined by using the rectal tube and the chromic-oxide method. The result was compared with that obtained by the total collection method. It was found that, except crude fiber, the value of digestibility of each nutrient of the commercial feed coincided closely in the two methods.
In experiment II, the digestibility of a pasture grass (Kentucky 31 Fescue hay) was studied by using the cloacal tube and the chromic-oxide method. At first the digestibility of the commercial feed was determined and then that of a feed composed of commercial feed and powdered pasture-grass hay in a proportion of 80:20. From the results obtained, it was found that the cock could digest the crude protein of pasture grass at a fairly high rate of 80% and its dry matter at a rate of as low as 30%.

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Little has been reported on how much the ingesta enters into the cecum from the ileum and how long it remains there. In this report data are presented on these points.
Four types of abdominal window were made by hand from celluloid plate. Each type has a small hole which can be opened and shut and from which such index substances as chromic oxide and barium sulfate can be injected easily into the terminal part of the ileum and the 15th or 17th segment of the cecum, respectively. Soon after the operation to sew an abdominal window, the rabbit restored to normal conditions and was fed about 120g of a diet cosisting of equal proportions of wheat bran, commercial mixed feed for dairy cows, and powdered hay. The rabbit was fed 20g of a diet in the morning and injected as mentioned above at about 11:30 a. m, Then the rabbit was returned to the cage and fed white clover. Cecal peristalsis was observed frequently. Four rabbits in Experiment I were killed 6 to 8 hours after normal cecal peristalsis appeared. Chromic oxide in feces, cecal contents, and contents of the colon and rectum was determined titrimetrically and barium sulfate in them was determined by the isotope dilution method reported by YOSHIHARA. Four rabbits in Experiment II were killed 3 hours after normal cecal peristalsis occurred. Determination of chromic oxide and barium sulfate was carried out as mentioned above.
The results are summarized as follows.
1. Of the 4 types of abdominal window, types 2 and 4 were better than the others for the purpose of injecting index substances into the intestine.
2. Carmine injected into the initial part of the colon was found in feces 2.33 hours, on the average, after normal cecal peristalsis appeared.
3. Three hours after normal cecal peristalsis appeared, 34.1 per cent of injected chromic oxide were found in the cecum. After 6 to 8 hours, 15.2 per cent were found.
4. Barium sulfate distribution was similar to that of chromic oxide in the large intestine.
5. It was confirmed that a portion of the intestinal contents entering the cecum from the ileum was forced into the sacculated colon passing by the cecum.

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Two roosters of the Single Comb White Leghornbreed with artificial anus and four adult male rats were fed on a protein-depleted diet for 8 days. Urine and feces were collected separately and analyzed for nitrogen contents by the Kjeldahl method and for glycine contents by the ninhydrin oxidation method.
The mean values of the metabolic fecal glycine, metabolic fecal nitrogen, and endogenous urinary nitrogen were 13.5, 45.0, and 213.9 mg per head per day, respectively, for the fowl and 8.3, 24.5, and 62.4mg per head per day for the rat.
From these results, it is evident that each yalue per 100g of body weight is smaller in the fowl than in the rat.

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For the purpose of computing the portion of sensitivity in the mammary duct area in mice 35 days of age, female mice were divided into three groups: (1) a spayed and estrogen-treated group, (2) an estrogen-treated group, and (3) an intact group. A standard dose of estrogen was given from 20 to 35 days of age. At 35 days of age areas of mammary ducts were measured. Based on the explanation of the variance of the mammary duct area in the three groups, analysis was made.
The portion of estrogen factor was approximately 10 per cent in the estrogen-treated group and 30 per cent in the intact group. The error portion was estimated to be 4 per cent in both groups. Thus the portion of sensitivity was estimated to be 86 per cent in the estrogen-treated group and 66 per cent in the intact group. The results obtained suggest primarily that emphasis should be placed on the sensitivity rather than the estrogen stimulator for mammary growth and that the use of estrogen-treated mice may be efficient than the use of intact female mice, when selection for mammary parenchyma is intended.
The author is grately indebted to Dr. M. NAITO for his kind advice on the work.

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In the previous paper it was reported that the blood cells of goat could be classified by two agglutinogens, G1 and G2, and two hemolysinogens, Y1 and Y2, contained in them. The present experiments were performed to clarify the existence and conditions of secretion of G1 and G2 antigens in goat saliva and milk by agglutination-inhition tests. The following results were obtained.
1) In some goats G1 and G2 antigenic substances were secreted in their saliva and milk, but in others they were not. So, goat saliva and milk may be classified into two types, secretor and nonsecretor.
2) When the frequencies of appearance of G1 and G2 antigens in the saliva were examined 75 cases of G1 blood type contained 48 cases (64%) of secretor type and 27 cases (36%) of nonsecretor type, and 12 cases of G2 blood type, one case (8.3%) of secretor and 11 cases (91.7 %) of nonsecretor type. When the milk was examined, 25 cases of G1 blood type included 18 cases (72%) and 7 cases (28%) of secretor and nonsecretor type, respectively, and one case of G2 blood type was of secretor type.
3) G1 or G2 antigen was secreted in both saliva and milk in 7 cases (28%) of the 25, only in the saliva in 3 cases (12%), only in the milk in 11 cases (44%), and in neither saliva nor milk in 4 cases (16%).

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Experiments were carried out to clarify the existence and conditions of secretion of antigenic substances of human blood groups (A, B and O substance) in saliva, milk, and cervicovaginal mucus of Holstein -Friesian cattle. The results obtained are as follows.
1) Saliva, milk, and cervicovaginal mucus of Holstein -Friesian cattle may be classified each into two types by antigenic substances of the human blood groups, namely, the secretor (A⁺, B⁺, and O⁺) and non-secretor (A^-, B^-, and O^-) types.
2) Frequencies of appearance of each blood group substance in saliva, milk, and cervicO^- vaginal mucus were examined. In 40 samples of saliva, type A⁺ was found in 90% (36 samples) and A^- in 10%(4); B⁺ in 65%(26) and B^- in 35%(14); and O⁺ in 65%(26) and O^- in 35 %(14). In 95 samples of milk, type A⁺ was found in 62.1%(59 samples) and A^- in 37.9%(36); B⁺ in 49.5%(47) and B^- in 50.5%(48); and O⁺ in 24.2%(23) and 0- in 75.8%(72). In 74 samples of cervicovaginal mucus, type A⁺ was found in 94.6%(70 samples and A^- in 5.4%(4); B⁺ in 91.9%(68) and B^- in 8.1%(6); O⁺ in 82.4%(61) and O^- in 17.6%(13).
3) When combinations of the blood group substances were examined, type A⁺B⁺O⁺(37.5% or 15 samples) in saliva, type A⁺B^-O^-(24.2% or 23 samples) in milk, and type A⁺B⁺O⁺ 73.0% or 54 samples) in cervicovaginal mucus showed the highest frequencies of appearance.
4) The quantity of each blood group substance in cervicovaginal mucus seemed to be larger than that in saliva and milk.
5) In the same individual, no correlation of secretion of each blood group substance between saliva, milk, and cervicovaginal mucus may be recognized.

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