Improvement was made in the method described in the first report. By using the improved method, called the HEIC method, it was possible to prove HCV constantly in tissue culture, without using swine. The neutralizing antibodies produced after the crystal violet vaccine (CVV) inoculation could also be measured. 1. In the new HEIC method, the period of culture of the first virus was extended to 9 days and bovine serum was removed from the composition of the second culture medium. This method made the demonstration of hog cholera virus (HCV) more practical than the original method. For example, the presence of HCV in the infected blood was proved up to a 10^-2 dilution by the original method; the new HEIC method showed a marked difference in sensitiveness and could prove HCV up to a 10^-5 dilution of the same sample. 2. By extending the incubation period from one hour to overnight, considerable progress could be made in the measurement of the NAT of swine vaccinated with CVV. The titer was 2.5 on the average by the virus dilution method. The titers of swine surviving after virus challenge were in a range of 3.5 to 5.0 by the serum dilution method. These tests were excellent in reproducibility. These titers were almost the same as the value obtained by the END method. 3. In the potency test of CVV conducted in the authors' laboratory, the relationship between the neutralizing antibody titer and the degrees of post-challenge reaction was examined in 39 swine. On the whole, swine which had a high NAT recovered from a slight clinical reaction. Swine which had a low NAT, however, showed a moderate or severe clinical reaction, and some of them could not survive after the challenge.

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The effects of P³²-adminisitration upon the testis of fowl were studied histologically and cytologically. In this study, immature and adult White Leghorn chickens were exposed to irradiation by intrapeitoneal injection of P³² (doses: 0.5-10μc/g). The results obtained are summarized as follows. 1) With the doses and intervals used in the present study, there was a delay in germ cell differentiation, but germ cells suffered no significant destructive effect in the immature birds. 2) Administration of a dose of 5μc/g seemed to have a lethal effect on an adult bird, which showed a significant decrease in size of the testis. Histologically, the tubules decreased in diameter, the germ cells became irregular in arrangement, and the spermatozoa and spermatids disappeared nearly completely. No vacuolization was observed in the germ cells and mitotic figures were rare. On the contrary, comparatively numerous karyolytic and pyknotic figures were present. 3) In adult chickens, some tubules of the testis decreased in diameter on the 30th day after injection of P³² (0.6μc/g). In such tubules, almost all germinal epithelia were of a single layer, consisting of spermatogonia and Sertoli cells only. Some other tubulcs, however, had stratified germinal epithelia containing mitotic secondary spermatocytes. These findings were considered as recovering evidence. 4) In adult chickens, when observed 10 days after administration of 0.5μc/g of P³², the germinal epithelium was a single-layered one. Mitotic cells were very few among the spermatogonia. The lumina of the tubules were filled with cell remnants. 0n the 20th day after administration, however, mitosis appeared among the spermatogonia. 5) In adult chickens injected with 0.5μc/g of P³², many abnormal mitotic figures were observed in the testes during 30 or 45 days after injection. These figures decreased in number with the lapse of time after injection. In those chickens, giant cells appeared in the testes by the end of the 2nd month and vacuolization in germ cells within 1 month after injection. These facts indicate that there are age differences and dose differences in the testis response of chikens to P³²-injection. 6) By the end of the 4th month after injection, germinal epithelia had recovered nearly completely. In one of the chickens showing such recovery, some tubules consisting of Sertoli-like cells alone and containing numerous spermatozoa in their lumina were observed among normal tubules.

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Ten adult cocks of the white Leghorn and Nagoya breeds were injected with India ink or Neoplen-Latex into the common carotid artery to use for the study of arterial supply of the spinal Cord. 1. The aa. spinales, which supply the spinal cord, originate from the following atteries:aa. vertebrales anteriores et posteriores, aorta descendens, and a. sacralis mediana. The spinal arteries are separated from these arteries either at the caudoventral (in the region of the a. vertebralis anterior) or the cranioventral portion of each spinal nerve. Moreover, each spinal artery divides into two branches, a. spinalis dorsalis et ventralis. 2. The dorsal spinal artery runs beneath the dorsal radices of the spinal nerves and separates into anterior and posterior branches. These branches anastomose with the same branches of the anterior and posterior dorsal spinal arteries. Therefore, the left and right tr. arteriosi spinales dorsales are formed. Both tracts are almost independent from each other, although they anastomose with each other only through the median arteries. These anastomoses have been formed along the dorsal midline of the spinal cord, with branches ramified medialwards from these tracts at the levels corresponding to the 1st to 3rd, 14th to 18th, and 20th to 24th spinal nerves. Many slender rami are given off lateralwards from these tracts. They fork further in the shape of T or Y anastomose with one another to form an incomplete thin afterial tract. This tract is called by the author the tractus arteriosus spinalis dorsalis accessorius. 3. On the ventral surface: of the spinal cord, the ventral spinal arteries are divided into anterior and posterior rami, which anastomose with the same rami of the contralateral arteries. In this way, the circuli arteriosi spinales ventrales are formed at such site as corresponding to the level of each spinal nerve. These arterial cycles vary in shape from rhomboidal to triangular, or parallel lines, according to the location. Each arterial cycle is connected with the cycles anterior and posterior to it by a median arterial tract, or tr. arteriosus spinalis ventralis. 4. The most cranial arteries are found at the level of the 3rd spinal nerve.

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