In oder to investigate the effects of cobalt-60 gamma ray irradiation on the body gains of rabbits aging approximately 50-day-old rabbits were subjected to single whole-body gamma irradiation externally. The results obtained were as follows: 1. There were significant differences of the body gains between control and treated groups except the 100 rads gamma-rays exposure group. 2. There were no differences in body gains between male and female rabbits. 3. Generally, the relation between gamma irradiated doses and the growth rates of rabbits were inversly proportional. 4. The $LD_{50}$ of the rabbits was 600 rads in case of single external whole-body gamma irradiation.

Hemogram and serum composition of pregnant rabbits were studied and the results obtained were as follows: 1. Erythrocyte, hemoglobin concentration and hemotocrit value of pregnant rabbits decreased at the late stage of gestation, and 1 week after delivery the values were recovered to the normal levels. Number of erythrocyte and hematocrit value were not found to be significant, but hemoglobin concentration showed significant differences at the third and fourth week of pregnancy. 2. Total leucocytes of pregnant rabbits increased continuously as gestation progresses and 1 week postpartum the values were returned to normal. Highly significant changes were observed in the third and the fourth week of pregnancy. Neutrophil was revealed highly significant rise at the third and the fourth week of gestation and 1 week postpartum, but lympocyte was decreased highly significantlly. 3. Serum calcium of pregnant rabbits revealed the tendency of decrease as gestation progresses and 1 week after delivery the value was returned to normal, and highly significant decrease was abserved at the fourth week. Serum inorganic phosphorus of pregnant rabbits showed highly significant decrease at the fourth week of gestation, but no differences were observed at the other period of gestation and 1 week postpartum. 4. Serum protein of pregnants rabbits showed the tendency of decrease continuously pregnancy progresses, and 1 week after delivery showed the normal values. Highly significant decrease was found at the fourth week of gestation. the levels of serum lipids in pregnant rabbits was unchanged untill the third week of pregnancy, but at the fourth week and 1 week postpartum, the rise was highly significant. The level of total serum cholesterol in pregnants rabbis was shown the tendency of decrease untill the end of the second week of gestation and significantly dropped at the third week, thereafter, the value was rose significantly at the fourth week of gestation and 1 week postpartum.

This experiment was carried out to investigate the effect on the liver of guinea pig after administration of 4.5mCi per Kg. body wt. with iodine-131. The histological changes in the liver were degeneration of hepatic cells, congestion of sinusoids, dilatation of bile ducts, perivascular infiltration of lymphocytes, and dissociation of hepatic cords. A marked histological changes were produced after treatment for 14 days and the morphological recoveries were observed 28 days after the treatment.

In native and Saanen goats, the thyroidal iodine uptake rate and its correlation between thyroidal activity and body gain were studied. The results were as follows: 1. The thyroidal iodine-131 uptake rate in native and Saanen goats were 10.46% and 21.26%, respectively, and the difference was statistically significant (P<0.01). 2. The correlation coefficients between monthly body gain and thyroidal iodine-131 uptake rate were -0.32 and -0.46 in native and Saanen goats, respectively. The correlations were negative and not significant between the rates.

견(犬)의 전좌폐(全左肺) 또는 좌폐하엽(左肺下葉)을 고무 낭(囊)으로 반복호흡(反覆呼吸)(rebreathing)을 연속(連續)시키며 폐동맥(肺動脈)(혼합정맥혈액(混合靜脈血液)) 및 폐정맥(肺靜脈)의 혈중탄산(血中炭酸)gas와 산소(酸素)를 반복호흡(反覆呼吸)한 폐포(肺胞)의 탄산(炭酸)gas 및 산소(酸素)와 비교(比較)하였다. 이들 두 기체(氣體)에 있어서 폐포(肺胞) gas의 장력(張力)이 혈액(血液) gas의 장력(張力)보다 항상 컸으며, 또 폐포(肺胞)와 폐동맥간(肺動脈間)의 경사도(傾斜度)가 폐포(肺胞)와 폐정맥간(肺靜脈間)의 경사도(傾斜度)보다 컸으나 탄산(炭酸) gas에 있어서만 유의성(有意性)이 있었다. 이 결과는 폐조직(肺組織)의 대사과정(代謝過程)에 의(依)하여 탄산(炭酸) gas가 생성(生成)되어 혈류(血流)로 운반(運搬)되어지기 때문이라 생각된다. 폐포(肺胞)와 폐정맥간(肺靜脈間)의 경사도(傾斜度)가 감소(減少)될때 폐동맥(肺動脈)과 폐정맥(肺靜脈)의 탄산(炭酸)gas장력(張力)의 차이(差異)는 증가(增加)하였고 마취심도(麻醉深度)와는 무간(無間)하였다. 본실험(本實驗)에서 반복호흡(反覆呼吸)을 하는 폐내(肺內)의 혐기성대사(嫌氣性代謝)(anaerobic metabolism)로 대사성산(代謝性酸)의 생성(生成)에 의(依)하여 폐(肺)를 통과(通過)한 혈액중(血液中) base exces 감소(減少)를 예측(豫測)할수 있었으나 그러한 증거(證據)는 없었다.

폐포(肺胞) gas와 폐동맥(肺動脈)(혼합정맥혈액(混合靜脈血液))만의 비교실험군(比較實驗郡)에 있어서도 역시(亦是) 탄산(炭酸) gas 장력(張力) 때로는 산소(酸素)까지도 폐포기체(肺胞氣體)의 장력(張力)이 더욱 높았다 (positive ${\Delta}Pco_2$, 및 $Po_2$). ${\Delta}Pco_2$는 산(酸) 또는 bicarbonate 주입(注入)으로 야기 되는 혈장(血漿) pH변화(變化) 및 시간(時間)에 따른 변이성(變異性)이 없이 항상 양성(陽性)을 보였으나, 혈중탄산(血中炭酸) gas장력(張力)의 크기에 비례(比例)하였다. 또 ${\Delta}Pco_2$ 는 혈류량(血流量)의 대소(大少) 및 분포(分布)에 별(別)로 영향 받지 아니하고 혈액내(血液內)에서 탄산(炭酸) gas평형(平衡)의 미달(未達)로부터 오는 것도 아니었으나 탄산탈수효소(炭酸脫水酵素) (carbonic anhydrase) 작용(作用)을 억제(抑制)할 때 증가(增加)되었다. ${\Delta}Po_2$는 더욱 변이성(變異性)이 컸으며 특(特)히 낮은 혈류속도(血流速度)에 있어서는 때때로 negative 현상(現像)을 나타내기도 하였다. ${\Delta}Po_2$도 또한 시간(時間) 및 혈장(血漿) pH 변화(變化)와 무관(無關)하게 독립적(獨立的)인 것이었으나, 탄산(炭酸) gas 장력(張力)의 변화(變化)로 일어나는 결과(結果)와는 반비례(反比例)의 관계(關係)가 있었다. ${\Delta}Po_2$도 gas교환(交換)이 일어날 수 있는 상당한 크기의 압차(壓差)를 주어도 존재(存在)하였고, 탄산(炭酸) gas 반응(反應)의 억제(抑制)에 의(依)하여도 영향받지 아니 하였다.

Hemagglutinating antigen of Toxoplasma gondii was prepared and purified by the method of a slight modification of Tsunematsu, and the preparation of the skin test antigen (toxoplasmin) was made by means of acetone-ether treatment described by Nobute et al. With these antigens the passive hemagglutionation and skin tests were performed for the diagnosis of swine toxoplasmosis by using artificially infected pigs. The results obtained were summarized as follows: 1. The hemagglutinating antibody and the skin test antibody were demonstrated one and three weeks after infection, respectively. And these antibodies were maintained over nine weeks after infection. 2. The antigenicity of hemagglutinating antigen was stable when it was kept in frozen state, while was unstable in a liquid state. 3. Freeze-dried skin test antigen (toxoplasmin) was stable for two months or more if it was kept at $5^{\circ}C$ and room temperature, but in the liquid or reconstituted state it was unstable. 4. Freeze-dried skin test antigen could be preserved without loss of antigenicity for more than two months. 5. Passive hemagglutination test could be applied effectively at the early phase of the disease process and skin test at later phase, mainly for epidemiological survey. However, by combiniation of these methods, the more accurate results could be obtained.

A survey of piroplasma infections, and trials of therapy of dairy cattle imported from Canada were conducted. The studies were carried out by hematological and clinical examinations, from May to September, 1970. The result obtained were summarized as follows: 1. A considerable damages due to Babesia and Theileria infections of dairy cattle were observed in several dairy farms where Pamaquine and Quinuroneum sulphate treatment was applied. 2. The infection was more commonly found in farms where Korean native cattle was raised previously. 3. The dairy cattle raised on pasture which is lightly infected with ticks were mostly infected with Theileria. The infected cattle were easily recovered after treatment with Pamaquine. 4. Leukocytosis and the left shift of neutrophils were observed in the cattle showing mixed infection with Babesia and Theileria.

Taenia were obtained from intestine of a weasel (Mustela sibirica coreana) captured at Gong Nung Dong, Seong Buk-gu, Seoul. The tapeworm was found to be Taeniarhynchus saginatus, and it was the first case of the wild carnivore in Korea.

Due to the fact that an inactivated anthrax vaccine may show no or lower immunogenicity and stability, a number of spore vaccines were exclusively used worldwide. In these studies non or less allergic strain of anthrax bacillus was selected and made a capsulated vegetative organisms. Anthrax organisms of a virulent strain were cultivated on sodium bicarbonate medium with or without adding I-alanine in which B. anthracis grew luxuriantly without forming spores. Inactivation of the organisims was carried out at $37^{\circ}C$ water bath for 3 days after the bacterial culture was mixed with formalin in a final concentration of two per cent. Aluminum hydroxide gel was added to the mixture of anthrax and blackleg bacterin. Guinea pigs were injected with the vaccine via subcutaneous or intramuscular route and challenged after three weeks, and the possibilities of protection was tested. Throughout the studies, the vaccines possibly protected the vaccinated guinea pigs more than 80 per cent compared to that of the controls. This experimental results strongly suggest that the vaccine may possibly applicable to the prevention of bovine anthrax and blackleg.

이 실험(實驗)은 뇌염(腦炎)바이러스(MVE virus)들 acetone, Tween-ether 그리고 Tween-ether-protamine-sulphate 로 처리한 후 그 바이러스가 지니고 있는 적혈구응집력가(赤血球凝集力價), 보체결합력가(補體結合力價) 그리고 감염력가(感染力價)의 변화 여부를 관찰함과 아울러 초원심분리법(超遠心分離法)에 의하여 이 바이러스가 지니고 있는 위의 세 가지 활성물질(活性物質)의 분획(分劃) 가능성(可能性)을 검토한 결과 다음과 같은 결과를 얻었다. 1) Acetone, Tween-ether 그리고 Tween-ether protamine-sulphate 처리에 의하여 MVE virus가 지니는 적혈구응집력가(赤血球凝集力價)는 8~16 배(倍)로 증가 하였다. 2) Acetone 및 Tween-ether 처리로 보체결합력가(補體結合力價)는 4 배(倍)로 증가 되었으나 Tween-ether protamine-sulphate 처리로는 저하되는 경향이 있었다. 3) Tween-ether로 처리하면 감염력가(感染力價)는 완전히 상실 되나 acetone으로 처리하면 $TCID50/log_{10}$ 3이 감퇴 되었다. 4) 위의 화학제의 처리와 관계없이 바이러스의 적혈구응집력가(赤血球凝集力價)는 $37^{\circ}C$ 에서 10 분간 가열(加熱)됨으로써 완전 소실 되었으나 보체결합력가(補體結合力價)는 상승 하였으며 이 활성도(活性度)는 $65^{\circ}C$ 에서 20 분간 까지도 계속 유지되었다. 5) 처리되지 않은 바이러스와 acetone 처리된 바이러스의 보체결합력가(補體結合力價)나 적혈구응집력가(赤血球凝集力價)는 Tween-ether 나 Tween-ether-protamine-sulphate 로 처리한 바이러스의 그것보다 열(熱)에 대해서 더 안정(安定)하였다. 6) 적혈구응집억제반응용(赤血球凝集抑制反應用) 항원제조(抗原製造)에 있어서 Tween-ether 로 처리하거나 acetone 으로 처리하여 만든 두가지 항원(抗原)은 모두 동일(同一)한 역가(力價)를 보였다. 7) 10~60%의 sucrose gradient centrifugation 에서 처리되지 않은 바이러스는 두개의 보체결합(補體結合)피크가 저농도(低濃渡)와 고농도(高濃渡)에서 각각 나타났으며 저농도(低濃渡)에서 얻은 재료는 적혈구응집력(赤血球凝集力)과 감염력(感染力)을 동반하고 있었다. 8) Acetone 으로 처리된 바이러스의 초원심분리(超遠心分離)에서는 위에 말한 두 보체결합(補體結合)피크 중 고농도부(高濃渡部)의 것은 감소 되었으나 다른 하나는 영향을 받지 않았다. 그리고 적혈구응집력가(赤血球凝集力價)가 증가된 반면 감염최고력가(感染最高力價)는 감퇴 되었으며 이 세 가지 활성(活性)은 acetone 처리 후에는 명확히 분획(分劃)되지 않았다. Tween-ether 로 처리된 바이러스는 초원심분리(超遠心分離)에 의하여 고농도부(高濃渡部)에 있는 보체결합(補體結合)피크는 완전 소실된 반면 저농도부(低濃渡部)에 있는 보체결합최고력가(補體結合最高力價)는 영향을 받지 아니 하였으며 이 피크는 감염력(感染力)을 동반하지 않는 적혈구응집소(赤血球凝集素)와 분획(分劃)이 가능 하였다.

The minimum inhibitory concentration (MIC) of five chemotherapeutic agents (penicillin, streptomycin, tetracycline, oxytetracycline and furazolidone) was measured for 126 strains of Staphylococcus aureus isolated from the udder of dairy cattle. The results obtained were as follows: 1. The MIC of penicillin, streptomycin, tetracycline, oxytetracycline and furazolidone ranged from 0.03 to 32 ug/ml, 0.06 to 128 ug/ml, 0.06 to 128 ug/ml, 1.0 to 512 ug/ml, and 0.06 to 32 ug/ml, respectively. The most frequent MIC of the above drugs were; penicillin 0.5ug/ml, streptomycin 1.0ug/ml, tetracycline 0.5ug/ml, oxytetracycline 4.0ug/ml, and furazolidone 2.0ug/ml. 2. The number of strains resistant to penicillin. streptomycin, tetracycline and oxytetracycline were 89(70.6), 9(7.1%), 10(7.9%), and 26(20.6%), respectively. Twenty-eight (29.2%) strains showed multiple resistance to more than two antibiotics tested.

Investigation of leptospiral antibody in Korean cattle and pigs was carried out from February to October, 1971. Ten different living antigens, namely L. icterohaemorrhagiae, L. canicola, L. antumnalis, L. hebdomadis, L. australis A, L. pomona, L. pyrogenes, L. grippotyphosa, L. bataviae and L. javanica, were used. A total of 590 Korean cattle and 460 pig blood samples collected from Seoul Majang-dong slaughterhouse were tested by the rapid microscopic agglutination test. Throughout the studies the following results were obtained and summarized. 1. Of 590 serum samples of Korean cattle 51 were positive(8.64%). 2. Of 460 serum samples of pigs 27 were positive (5.87%). 3. Of 51 positive cattle samples, 29(4.92%) showed antibody to a serotype of L. icterohaemorrhagiae and 18(3.0%) to L. canicola, and 4 (0.68%) to L. pomona. Eight of L. icterohaemorrhagiae positive samples showed a cross reaction to L. canicola. 4. Of 27 positive pig samples, 14(3.04%) showed antibody to L. ictereohaemorrhagiae and 7(1.52%) to L. grippotyphosa. 4(0.87%) to L. canicola, 2(0.43%) to L. pomona. Two of L. canicola positive samples showed a cross reaction to L. grippotyphosa. 5. Serum samples of seven pigs, showing antibody positive to L. grippotyphosa were first observed in Korea. 6. Infection rate of bovine and porcine leptospirosis, in Korea, appeared to be lower than that of Japan, Taiwan, Thailand and the Philippines.

Studies on modified complement fixation (MCF) test of antiblackleg bovine serum were made and the results obtained were summarized as followings. 1. The most satisfactory antigen for the MCF test among various materials studied was found to be the vegetative cells of Cl, chauvoei grown in cooked meat medium (CMM) containing 0.5mM l-(alpha) alanine and 0.1mM manganese. The antigen was prepared by inoculating the spores of Cl. chauvoei, heated at $70^{\circ}C$. for 30 minutes, into the CMM followed by incubation at $37^{\circ}C$. for 15 hours. 2. An active component contained in the factor serum of fresh normal rabbit serum was found to be C'4 fraction. It was also shown that, furthermore, DEAE cellulose sieved C'4 fraction of the factor serum enhanced antibody titer and the highest antibody titer was resulted by the addition of 0.03 ml, of the factor serum to each tube. 3. More than four fold increases of antibody titer, in antiblbckleg bovine serum-antigen system, was made with the MCF test than that with the direct complement fixation test. 4. The MCF antibody titer of cattle vaccinated against blackleg was 128 until seven month and 64 for five months thereafter.

The pneumonic lungs of 51 pigs, from which the presence of pasteurella organisms was confirmed by bipolar staining, were examined pathologically. The numbers of pigs in each age group were 22 (43.1%) in 3-4 month group, 20 (39.2%) in 1-2 month group, 7 (13.7%) in 5-6 month group, and 2 (4.0%) in group of more than one year. The lungs of 16 pigs which were regarded as pasteurella pneumonia without any other manifestations were studied pathogically. Grossly, the affected lungs showed pulmonary edema, lobular consolidation and interlobular edema. Pigs over 3 months of age frequently showed chronic condition in which the entire lobe was involved as confluent pneumonia. In such pneumonic lungs, infarction and focal necrosis of the lung parenchyma and deposition of fibrinous exudate on the pleura were encountered. Histologically, the alveolar spaces were filled with fibrinous and leukocytic exudates. The interlobular septae showed marked edema and fibrinous exudate. The process of organization was frequently observed in chronic cases.

Experimental studies on the water content of muscles and the histological changes of muscles, digestive tract and kidney, influenced by forced oral administration of excessive tap water, were performed by using 10 Korean bulls. Experimental animals were divided into two groups, five heads for test group and five for control group. All of the bulls used in this experiment were weighing between 250 kg and 300 kg and 3 and 4 years of age. In each test animal, a total of 140 litters of tap water was passed in the forestomach by means of catheterization within 12 to 18 hours. And each of them was slaughtered immediately after the animals showing symptoms of respiratory distress. In control group, the animals were allowed to drink tap water normally. From test and control animals after slaughter, each 10 gm of M. biceps femoris, M. satorius, M. adductor, M. gluteous supercialis, M. iliocostalis lumborum, and M. transversus costarum were taken from definite parts in order to measure water content. In the histopathological studies tissues of rumen, reticulum, omasum, abomasum, duodenum, colon and kidney were taken as wall as the above mentioned muscles. The results obtained were as follows; 1. Increase of water content in the muscles of test group were 4.6% in M. satorius, 4.24% in M. transversus costarum, 4.14% in M. gluteous supercialis, 4.02% in M. adductor, 3.88% in M. biceps femoris, and 2.46% in M. iliocostalis lumborum respectively. The highest increase was found in M. satorius and the lowest in M. iliocostalis lumborum. 2. In test animal, average increasing value of water content in muscles was 3.9% and shown highly significant (p<0.01). 3. On the microscopical findings of carcass, marked watery edema was observed all of the subcutaneous tissues and intermuscular connective tissues. 4. Microscopically, the epimysium, perimysium and endomysium were widened, and the muscle fibers were lacerated. The cells of stratum lucidum in the epithelium of rumen and reticulum were shown marked vacuolization. In the kidney, dilatation of Bowman's spaces and proximal tubles was observed.

Estrous and non-estrous rabbits were inoculated with E. coli or Streptococcus pyogenes, and the mixture of the two organisms, and bacterial count and histopathological studies of uterine horns were made to observe the effects of estrogen on the resistance of the uterus to bacterial infection. The results obtained were summarized as followings; 1. Four hours after inoculation of bactoria into uterine horn, the number of organisms was significantly lower in estrous rabbits than in non-estrous regardless of the kind of organisms inoculated. 2. The highest reduction rate of the organisms among the three bacterial inoculation groups was found in estrous rabbits inoculated with E. coli, and the lowest reduction rate was with Streptococcus pyogenes. 3. Histopathological changes of uterine horns induced five days after bacterial inoculation were observed. In estrous rabbits, a mild inflammatory reaction was found in Streptococcus pyogenes group, but a slight inflammatory reaction and only a negligible inflammatory reaction were observed in mixed bacteria group, and in E. coli group respectively. In non-estrous group, however, a marked inflammatory reaction was observed in Streptococcus pyogenes group, a moderate inflammatory reaction and a slight inflammatory reaction were observed in the mixed bacterial group and E. coli group, respectively.

1. Of 4,112 earth worms, 3,480 were classified as Eisenia foetidae, and 3,277 of the species were infested with the larvae of Metastrongylus apri. 2. Cresol and $CaCN_2$ were found effective in the insecticidal test of earthworms. 3. The nose ring was effective, in pigs, to prevent digging and eating the earthworms and resulted a lower lungworm incidence in pigs. 4. The best place to put the nose ring was the nasal septum.