The effects of halothane and pentobarbital sodium anaesthesia in implantation and maintenance of pregnancy were compared in the rabbit ovariectomized the day after insemination and given steroid replacement therapy. The result has shown that halothane anaesthesia did not favour the overall process of implantation or foetal development, compared with pentobarbital sodium.

난소를 제거한 가토에 있어서 부신에서 분비되는 oestrogen이 착상에 충분할 가능성이 있음에 비추어 이 실험에서는 가토에서 oestrogen의 근원이 되는 난소와 부신을 함께 제거하여도 착상이 여전히 일어나며 임신이 유지되는가를 실험하였다. 이 실험결과는 다음 두가지 점을 밝혀주었다. 1. 부신에서는 가토의 착상에 충분한 oestrogen을 분비하지 아니하였다. 2. 가토의 착상과 임신유지는 oestrogen 없이도 가능하였다.

In oder to investigate the effects of cobalt-60 gamma irradiation on the postnatal body gains and the other influece of the pregnant mice were subjected to single whole-body gamma irradiation externally. The results obtained were as follows: 1. The all mice of 400, 600, and 800 Rads gamma-irradiated groups showed abortion after prenatal gamma irradiation within 4 to 9 days. 2. There were significant differences of the postnatal body gains of mice between the control and treated groups (100 Rads and 200 Rads gamma irradiation). 3. The relation between gamma-irradiated doses and the postnatal growth rates of mice were inversly proportional.

In order to investigate the longevity of the reticulocyte in peripheral blood, samples were taken from the jugular vein at birth; 2nd, 4th, 7th, and 14th day after birth in eight healthy Korean native goats (body weight 1.5 to 2.0kg). The samples were stained in 1, 2, 3, 4, 6, 10, 24, and 48 hours after bleeding, and observed the reduction in the number of reticulocytes and the degree of the staining. The data have shown that the number and staining degree of reticulocytes in Korean native goots were appeared as normal untill 24 hours after bleeding, however, the number and staining degree were reduced in 48 hours after bleeding.

The serum albumin phenotypes and the gene frquencies of 100 Korean native goats were examined by starch gel electrohporesis. The results obtained were as follows: 1. The albumin phenotypes were classified as Alb AA, Alb AB, and Alb BB and the frequencies of appearence were 10, 12 and 78%, respectively. 2. The genetic factors of serum albumin were observed as Alb A and Alb B and the rates of gene frequencies were 16 and 84%, respectively.

Eight cattle and ten sheep were administrated various degree of PMA-B and EPN, and S-GOT, S-GPT and serum cholinesterase activity were tested. Serum cholinesterase activity showed no typical tendency, however, S-GOT/S-GPT ratios were decreased by the administration of PMA-B. It was suggested some degree of liver damage by the administration of the chemicals was recognized.

개에 자연발생(自然發生)한 다음과 같은 종양(腫瘍)을 수집(蒐集)하여, 그 육안적(肉眼的) 및 조직학적(組織學的) 소견(所見)을 검토(檢討)하고, 이에 관(關)한 간단한 고찰(考察)을 가(加)했다. 피부(皮膚) 및 피하직(皮下織)의 종양(腫瘍) : 섬유종(纖維腫), 지방종(脂肪腫), 표피성(表皮性) 낭종(囊腫), 흑색육종(黑色肉腫), 한선종(汗腺腫), 비만세포종(肥滿細胞腫)(2예(例)), 비만세포육종(肥滿細胞肉腫), 피지선암종(皮脂腺癌腫). 비장(脾臟) 및 임파절(淋巴節)의 종양(腫瘍) : 비피막(脾被膜)의 섬유육종(纖維肉腫), 비(脾)의 평활근육종(平滑筋肉腫), 임파절(淋巴節)의 임파육종(淋巴肉腫)(2예(例)). 폐장(肺臟)의 종양(腫瘍) : 기관지성암종(氣管枝性癌腫)(3예(例)), 각각(各各) 선암종형(腺癌腫型), 편평세포암종형(扁平細胞癌腫型) 및 미분화세포(未分化細胞)(원형(圓形))암종형(癌腫型). 소화관(消化管) 및 간장(肝臟)의 종양(腫瘍) : 위(胃)의 섬유종(纖維腫), 간(肝)의 혈관종(血管腫), 담관암종(膽管癌腫), 간세포암종(肝細胞癌腫), 간(肝)에 출현(出現)한 골수성백혈세포세포(骨髓性白血細胞細胞). 복막(腹膜)의 종양(腫瘍) : 섬유육종(纖維肉腫). 비뇨생식계(泌尿生殖系)의 종양(腫瘍) : 자궁(子宮)의 섬유종(纖維腫), 난소(卵巢)의 난포낭종(卵胞囊腫), 질(膣)의 전염성(傳染性) 성기종(性器腫)(6예(例)), 신암종(腎癌腫), 섭호선종(攝護腺腫)(2예(例)), 포피(包皮)의 섬유종(纖維腫), 고환(睾丸)의 정충종(精蟲腫). 유선(乳腺)의 종양(腫瘍) : 혼합종(混合腫)(2예(例)), 근상피종(筋上皮腫). 신경계(神經系)의 종양(腫瘍) : 대퇴부(大腿部)의 신경섬유육종(神經纖維肉腫).

The authors believe that farm livestok will be greatly affected by the marked increasing use of organic phosphate. This study was carried out to observe the clinical signs and histopathological changes of mouse, guinea pig, hamster and rabbit that were orally administered with diazinon used usually as agricultural insecticide, and cholinesterase (ChE) activity was histochemically examined in the liver, heart, kidney, adrenal gland, duodenum and salivary gland of these experimental animals administered with diazinon. The results obtained were as follows: 1. Clinical signs such as dullness, severe salivation, ataxia, dyspnea, irregular slight convulsion and inappetance and as the histopathological changes cloudy swelling, congestion and hemorrhage of parenchymal organs, catarrh or local necrsois of the gastrointestinal tract, congestion or hemorrhage of the other organs were observed. Especially, hemorrhage of adrenal glands (rabbit, guinea pig) and pulmonary congestion and hemorrhage were necessarily constant. 2. In the histochemical study, ChE activity appeared intensely in the liver, heart, medulla of adrenal glands and salivary glands (submaxillary and parotid) of control animals, but ChE activity was negative or markedly decreased in experimental animals administered with diazinon. There was no marked difference between the control and experimental animals in ChE activity of the kidney. 3. Histochemical observation of ChE activity was helpful to explain the clinical signs and histopathological changes and was regarded as a diagnostic method for organic phosphate poisoning.

Experimental studies were performed to observe the effect of exposure to 100% oxygen in 2 atmospheres on the lung tissue of rats, and to examine the resistant effect of DL-${\alpha}$-tocopherol. The following results were made through this experiment: 1. Half-lethal time by oxygen poisoning was longer in tocopherol treated group than not treated group. 2. Ratio of lung weight to body weight was significantly higher in fatal group within half-lethal time than survival group (p<0.01). 3. Histopathological changes of the lung by oxygen toxicity were vascular congestion, pulmonary edema, hemorrhage and emphysematous change. The degree of changes were rather marked in experimental group than tocopherol untreated group. Those were regard as the changes being occurred during tolerance process by prolonging half-lethal time.

In this study two sets of experiments were undertaken. Firstly, the embryonated eggs and first-stage larvae, sprayed in disinfected soil, were exposed to different temperatures. Then, the viabilities of them were weekly determined by inoculating the soil to earthworms, Eisenia foetida. Secondly, the infective larvae, seperated from the earthworms and suspended in tap water, were also exposed to different temperatures and their viabilities were checked microscopically at weekly intervals. The results were summerized as follows: 1. The maximum longevities of embryonated eggs and first-stage larvae were determined as 1 week at $35^{\circ}C$, over 36 weeks at $25^{\circ}C$, $15^{\circ}C$, and $5^{\circ}C$, 32 weeks at $-5^{\circ}C$, and under 1 week at $-15^{\circ}C$. 2. The mean numbers of infective larvae detected from the test earthworms were greatest at $5^{\circ}C$, and decreased with rise or fall of the temperature. 3. Infective larvae freed from the intermediate host were able to survive for 2 weeks at $25^{\circ}C$ and 3 weeks at $15^{\circ}C$. However, they lost their viabilities in a week at $35^{\circ}C$, $5^{\circ}C$, $-5^{\circ}C$, and $-15^{\circ}C$. 4. The number of living infective larvae at $15^{\circ}C$ was greater than at $25^{\circ}C$.

The poxvirus group is considered to be a typical cytoplasmic inclusion forming virus. Every poxvirus has been reported to produce only one kind of inclusion in the infected tissues. A vague concept that inclusions of poxviruses are eosinophilic or acidophilic has prevailed. Although many papers and theories about the nature of the inclusion have been presented, most of them are not quite convincing on the point of the relations with virus multiplication, and an analysis of papers published showed that there seem to be many discrepancies in the descriptions of the nature of the poxvirus inclusions. Comparative studies on host-virus interaction with cowpox, orf, swinepox and fowlpox viruses which selected from each Group (I-IV) of poxviruses were performed from the morphological and virological standpoints. At first, in cowpox virus-FL cell system, as a comparative model, cytoplasmic inclusion, nucleic acid metabolism by autoradiography and detection of viral antigen by immunofluorescence were studied and obtained the results as follows: 1. The focus-like cytopathic effect (CPE) at early stage developed to entire culture at terminal stage of infection, and also the developing status of CPE was correlated to viral doses for inoculation. Two kinds of cytoplasmic inclusions which named A and B type were easily observed by Giemsa, hematoxylin-eosin (H & E) and May-Greenwald Giemsa (MGG) stainings in the infected cells. The B type inclusions were formed at early stage of infection and the A type inclusions were produced subsequently the B type formation. The B type which common type inclusion in poxviruses was a small compact or aggregate at early stage and developed to a large diffuse body at terminal stage of infection. On the other hand, the A type inclusion which depend upon the kind of virus was appeared as round and discrete shape, and its size and number was increased gradually during the culture period. It was characteristic to form distinct halos around the both types of inclusions in acid fixed, H & E stained preparations of infected cultures. The B type inclusion was always positive in Feulgen reaction and showed as DNA containing body but the A type inclusion was not. 2. In the relationship between inclusion and DNA metabolism of infected cells by the qualitative autoradiography using 3H-thymidine, the appearance of silver grains was coincided with B type inclusion but not with A type inclusion. This showed that the DNA synthesis was proceeded in all B type inclusions except those in the terminal stage with a diffuse form. This suggested that the B type inclusions are only sites of DNA synthesis and this was proceeded after the cell infection independently. The activity of DNA synthesis of the inclusions was nearly the same as that of the nucleic of normal cells and non-inclusion bearing cells. and non-inclusion bearing cells. Regardless of the size of the degree of DNA synthesis of the B type inclusion, inclusion bearing cells all showed remarkable suppression of nuclear DNA synthesis. 3. By the direct fluorescent antibody technique viral antigen in infected cells was detected. The B type inclusions have been proved to contain a great deal of viral antigen, whereas the basic substance of A type inclusion did not show antigenicity except the round edge. It was suggested that the round edge fluorescence might be caused by the glare of cytoplasmic viral antigen which pushed out and concentrated by the A type inclusion development. 4. Hemorrhagic red pock formations on chorioallantoic membrane of embryonated chicken egg had proved the characteristic of used viral strain. 5. By the above studies on the nature of two types of inclusions and the role they play in virus multiplication, it was concluded that the B type inclusion must be the site of the synthesis of viral DNA and protein as well as the site of the virus.

A Total of 173 streptococci isolated from 536 dairy cattle in Gyeonggi Province identified by Lancefield serological reaction and other biological properties. Antibiotics sensitivity test was also examined and the results obtained were as follows: 1. A total of 173 isolates of 167 strains (96.5%) were reacted with group A,B,C,D,E and G antisera. 2. Of the 167 positive strains, 75 strains were identified to Streptooccus uberis, 56 to Streptococcus agalactiage and 26 to Streptococcus dysgactiae, respectively. Also, Sreptococcus pyogenes, group D and group G streptococci were rarely isolated. 3. In results of antibiotic sensitivity tests, the most isolates were sensitive to leucomycin and erythromycin but less sensitive to streptomycin. and kanamycin.

The rate of growth of Leptospires were studied by culturing in Korthof's media and Cox's liquid media which were treated at four different temperatures. The effect of thiamine hydrochloride in the culture of leptospires were also studied. The results obtained were summerized as followings: 1. The best growth of Leptospira icterohaemorrhagiae and Leptospira canicola was observed in Korthof's media with the rabbit serum heated for 60 minutes at $56^{\circ}C$. 2. A good degree of growth of Leptospira icterohaemorrhagiae and Leptospira canicola was observed in both Cox's liquid media with rabbit serum heated for 30 minutes at $100^{\circ}C$ and with fresh rabbit serum. 3. The growth of Leptospira was enhanced by adding small amount of thiamine to the both media which were shown to be unsatisfactory for the growth of the organisms. 4. Culture of leptospires were attained by simply heating for 30 minutes at $100^{\circ}C$ both Korthof's media and Cox's liquid media containing rabbit serum obtained without aspetic procedures.

A total of 119 raw milk samples from ten dairy farms were examined for total bacterial count, and 739 quarter milk samples of 118 dairy cows of 14 herds were examined for mastitis. The results obtained were as follows: 1. The mean of total bacterial counts of the 119 raw milk samples was 132,000 per ml. The total bacterial counts of 81 samples (68.1%) were under the standard of 100,000 per ml and those of the 38 samples (31. 9%) were over the standard. The number of bacteria showed a tendency to increase in summer. 2. One hundred and ninety five quarters (26.4%) of 98 cows (52.7%) were proved to be infected with mastitis. Clinical mastitis was found at 7 qtarters (3.5%) of 5 cows (5.0%). 3. Staphylococcus (44.9%) and Streptococcus (26.7%) were two main causative organisms of mastitis. Coliform bacteria (4.6%), Pseuedomonas spp. (4.6%), yeasts (1. 3%) and corynebacterium sp. (0.7%) were also isolated from the infected quarters. 4. The isolates were more sensitive to chloramphenicol ((96.1%), leukomycin (78.8%), streptomycin (75.5%) and tetracycline (72.4%). On the other hand, they were less sensitive to colistin (11.0%), oreandomycin (18.1%), sulfisoxazole (24.6%), penicilline (27.6%), kanamycin (43.3%) and erythromycin (49.7%). Especially the strains of Pseudomonas spp. isolated from the infected quarters were resistant to almost all the drugs examined.

In order to compare the diagnostic value of Modified California Mastitis Test (MCMT), Modified Whiteside Test (MWT) and Resazurin Reduction Test (RRT) using the direct microscopic leucocyte count (DMLC) as standard, a total of 739 quarter milk samples were examined. The results obtained were as follows: 1. Of the 739 samples, 24.4% had positive DMLC value (over 500,000 leucocytes per mI.), 32.6% positive MCMT reaction, 34.9% positive RRT reaction and 39.9% positive MWT reaction. 2. The identical ratings of the three mastitis screening tests with DMLC values were 60.7% (MWT), 61. 8% (MCMT) and 72.1% (RRT). 3. The mean reaction values of the predicted mastitis screening tests were $1.09{\pm}0.01$ (MWT), $1.12{\pm}0.06$ (MCMT) and $1.25{\pm}0.40$ (RRT). The efficiency ratings of them were 34.8% (MWT), 49.3% (RRT) and 55.0% (MCMT) respectively.

The susceptibility of 536 isolates of Staphylococcus and 313 isolates of Streptococcus to a number of chemotherapeutics were studied. These organisms were isolated from bovine mastitis during 1973 and 1974. In addition to this, the rate of multiple resistance of 425 isolates of Staphylococcus and 164 isolates of Streptococcus, isolated in 1974, to the chemotherapeutics was analysed. The results obtained in this work were summerized as follows: 1. Staphylococcus and Streptococcus isolated in 1974 showed a higher resistance, with 3 exceptions of chemotherapeutics, than the isolates of 1973. 2. Staphylococcus isolated in 1973 and 1974 showed a higher susceptibility than Streptococcus. 3. The strains of Staphylococcus resistant to colistin were 39 strains (9.2%), to colistin and sulfisoxazole 33 (7.8%), to streptomycin, kanamycin, colistin and sulfisoxazole 20 (4.7%), and to penicillin, colistin and sulfisoxazole 18 (4.2%). 4. The strains of Streptococcus resistant to colistin were 17 strains (10.4%), to streptomycin, kanamycin, colistin and sulfisoxazole 13 (7.9%), to colistin and sulfisoxazole 11 (6.7%) and to penicillin, colistin and sulfisoxazole 11 (6.7%).

A total of 2,065 quarter milk samples of 534 dair cows from 35 herds were examined for mastis and the results obtained were as follows: 1. 654 quarters (31.6%) of 301 dairy cows (56.3%) from 34 herds (97.1%) were infected with mastitis. It was found that 8 cows (1.5%) showed clinical mastitis and other cows were subclinical. 2. Low infection rate of mastis was shown in first delivery cattle and higher infection rate in more deliverable of cattle. 3. The main causative organisms of the matitis were Staphylococcus aureus (19.4%), Streptococcus agalactiae (11.3%) and Streptococcus dysgalatiae (5%). 4. The majority of causative organisms were very resistant to colistin and highly sensitive to tetracycline. Especially Streptococcus strains were highly sensitive to leukomycin, and Staphylococcus aureus were highly sensitive to tetracycline and the other bacteria were highly sensitive to tetracycline and kanamycin.

1. The daily gain of the artificially induced cryptorchid pigs increased when compared with that of the castrated pigs, but less than that of the non-treated normal pigs. 2. The meat quality was only partially improved as the sex odor was not completely eliminated by inducing cryptorchidism. 3. Exogenous gonadotropins could not induce the normal spermatogenesis in the cryptorchid swine.

The effect of mecadox, trade name of carbodox, in the treatment of colibacillosis and in the prevention of experimental Salmonella infection in swine was studied throughout the experimental period of four weeks using a total of 70 piglets. The results obtained are as followings. 1. Mecadox was found moderately effective as a therapeutic for colibacillosis of piglets when administered orally as pig doser or added to the feed at the ratio of 50 ppm with or without the addition of vitamin A and $D_3$. 2. In the prevention of experimental infection with Sal. choleraesuis, mecadox was found highly effective. As judged by clinical symptoms such as diarrhea and fever together with the confirmation of excretion of the causative organisms in the feces, the best result was obtained with mecadox pig doser followed by mecadox (50ppm) with vitamin A and $D_3$, and mecadox (50 ppm) without the vitamins in the descending order of effectiveness.

By means of vinylite-corrosion technique, the distribution of the portal vein within the liver in 50 Korean native goats was observed. The portal vein consists of the following principal branches; Truncus sinister vanae portae et dexter, Pars transversa trunci sinistri, Pars umbilicalis trunci sinistri, Ramus lateralis lobi sinistri, Ramus medialis lobi sinistri, Ramus medialis lobi dextri, Ramus lateralis lobi dextri, Ramus dorsolateralis, Ramus caudatorum. In the goat Pars transversa trunci dexter could not be recognized.

By employing the vinylite-and neoprene latex-corrosion technique, ramification and arrangement of A. renalis were observed in fifty Korean native goats (100 kidneys). The obtained results were as follows: 1. A single renal artery, arising on each side from abdominal aorta, bifurcated into Ramus dorsalis and Ramus ventralis from which 3~6 segmental arteries originated. 2. The dorsal and ventral surfaces of the kidney were divided separately into 3~6 arterial segments by the running of the segmental artery into the parenchyma. Of them four segments were mostly frequent (in 77% of right kidney and 83% of left). 3. In 25 of all the kidneys, either dorsal or ventral surface of a kidney was supplied from interlobar or segmental arteries belong to the opposite Ramus. 4. In 3 goats, A. polaris superior was observed. 5. Generally, distribution of the renal artery of Korean native goat resembled that of the dog.

한국산 aflatoxin의 독성을 비교 규명하기 위하여 결정 aflatoxin, 사료배합 aflatoxin 및 표준 aflatoxin을 오리병아리에 각 1회씩 경구투며 또는 급식시켜 얻은 결과는 다음과 같다. 1. 각종 aflatoxin의 독성으로 인하여 유발된 공통된 주요 병리조직학적 병변은 출혈(出血), 간세포(肝細胞)의 괴사(壞死), 지방변성(脂肪變性) 및 담관세포(膽管細胞)의 증식(增殖) 등이였다. 2. 병변(病變)의 정도(程度)는 독소의 투여량과 경과시간에 따라 다양(多樣)하게 나타났다. 3. 한국산 aflatoxin의 독성은 표준 aflatoxin에 비해 약간 더 심한 병변(病變)을 나타냈으며, 한국산 aflatoxin에서도 결정 aflatoxin을 투여한 경우보다 사료에 배합하여 급식시킨 경우가 약간 더 심한 병변(病變)을 나타냈다. 4. 닭병아리의 간장에서 aflatoxin이 유발시킨 병리조직학적 소견보다 오리병아리의 간장에서의 경우가 그 정도에 있어 더욱 심하고 뚜렷하였다.