The purpose of this paper is to know the cause of a rapidly fatal disease of Korean native cattle commonly occurred in the farm-houses in Gyeonsangbugdo district and the rest of the country. The author diagnosed this acute fatal disease of Korean native cattle as enterotoxemia due to Clostridium perfringens based on the clinical, epidemiological and pathological findings.

The present study was underve the histochemical nature of various follicles and interstitial tissues in the ovaries of Korean native goats and cattle as well as the histochemical changes of those in the ovaries of Korean native goats treated with dexamethasone. Much more lipid granules appeared in the granulosa and theca cells of atretic follicles compared with normal follicles in these ruminant ovaries. In the ovaries of Korean native goats the interstitial tissue derived from the theca interna of atretic follicles appeared the form of patches of cells and the interstitial tissue derived from stromal cells appeared the form of diffuse, obscure bounds. In the ovaries of Korean native cattle the interstitial tissue derived from theca interna of atretic follicles showed sparsely scattered form of pathes of cells. The histochemical components were described on the basis of lipids in the granulosa and theca cells of normal follicles, atretic follicles and interstitial tissue. In the ovaries of Korean natve goats treated with dexamethasone, the granulosa and theca cells of atretic foillicle contained plenty lipid granules that were increased in size and number, however, lipid granules were markedly decreased in the interstitial tissue.

The smears and tissue sections of organs (liver, lung, kidney, heart, lymph-node, brain) were carried out to compare the detection of parasites in the splenectomized calves artificially infected with B. bigemina and B. argentina, respectively. The results obtained from this experiment were abstracted as follows: 1. In the calves infected with B. argentina the parasites were easily detected by the blood smears and tissue smears but, particularly, the detection of parasites in the kidneys and brain by tissue smears and tissue sections was greater useful. In this experiment, the packing of the parasite-infected red blood cells was found in the capillary vessels of the organs. 2. When the fresh infected-brain was kept at $5^{\circ}C$ refrigerator, Babesia argentina could be detected during 9 days from the brain smears. According to this results, we could do differentiate the parasites from the brain of the dead animal by the doubtful babesiosis in the field. 3. If we use the brain smears and brain sections in order to survey or detect Babesia infections of cattle in Korea, these methods could be worthwhile for the differential diagnosis of B. argentina and B. bigemina.

During the period of March, 1976 to December, 1976, 48 raw milk samples were taken from dairy cows at 48 different dairy farms in Korea analyzed by gas liquid chromatography to determine the seasonal variation of the amount of organochlorine pesticide residues. At the same time 80 market milk, 10 beef and 10 pork samples were analyed by the same procedure for checking residual levels. The results were summarized as follows; 1. Milk samples from 17 dairy farms (36 per cent of tatal) were shown to be contaminated with various organochlorine pesticides. The residua lrate of ${\gamma}-BHC$ in tested samples were 44per cent (14 sam ples) that of aldrine was 28 per cent (9 samples) and those of pp'-DDT, dieldrin and heptachlor were 9.3 percent (3 samples) respectively. 2. In raw milk pp'-DDT, ${\gamma}-BHC$, aldrin, dieldrin and heptachlor were detected, and aldrin, dieldrin and heptachlor were detected in the market milk. Any kinds of organochlorine pesticides were not detected in beef samples but dieldrin and heptachlor were detected in pork samples. Average residual values of aldrin, dieldrin and heptachlor in the market milk were 0.0077 ppm (0.0000~1.1100 ppm), 0.0001ppm (0.0000~0.0500 ppm) and 0.0008 ppm (0.0000~2.0520 ppm), respectively, and those of dieldrin and heptachlor in pork samples were 0.0010 ppm (0.0000~0.0100 ppm) and 0.0033 ppm (0.0000~0.0330 ppm). respectively. 3. Residues of organochlorine pesticides in raw milk were extremely variable; in fact pp'-DDT was detected in milk samples from A, B, C and D districts and endrin was not detected from all districts. The ${\gamma}-BHC$ and dieldrin were detected at the district of A, C and D, aldrin at the districts of A and C and heptachlor at the districts of both A and D. 4. Seasonal trends of residual values of organochlorine pesticides were, in general, noticeable. The residual level was much higher in Spring than in other seasons and showed the tendeney of decrease from spring through summer and autumn generally; in the case of pp'-DDT average residual values were 0.0121 ppm in spring, 0.0022 ppm in summer and not detected in autumn. But in winter ${\gamma}-BHC$ and aldrin residues were increased a little. Residual values in raw milk (when cow are fed on hay and silage) were appeared higher in winter than the other seasons. 5. Residues of organochlorine pesticides in raw milk were not related in respect to hygienic conditions of dairy farms pp'-DDT and heptachlor were, in general, detected in all farms and aldrin was more detected in milk from well sanitated farms than poor sanitated ones.

The distribution of coliform population and drug-resistant coliforms in Shinchun water during April to August in 1976 and R factors in resistant strains were studied. The mean coliform population in the stream water was 361 organisms per 0.1ml and 53.5% of total coliforms were fecal coliforms. Thritynine and a half percent of total coliforms were streptomycin (SM) resistant to one or more of following antibiotics; tetracycline (TC), chloramphenicol (CM), ampicillin (AP) and kanamycin (KM). The most frequent resistant pattern was triple resistance to SM, TC and AP (23.8%) and followed by quadruple one to SM, TC, CM and AP (17.5%). About 87 percent strains carried R factors which were transferable by conjugation to E. coli ML 1410 or S. typhimurium LT 2.

In this study, the serological survey on bovine babesiosis was conducted using indirect fluorescent antibody technique. A total of 472 serum samples were taken and tested with the following results. 1. 63.3% or 299 out of 472 serum samples were positive against bovine babesiosis. 2. The positive rate in Seoul, Jeon-buk and Jeju areas were 63.8, 30.6 and 91.4 per cent, respectively. 3. In spring, the rate of positive reaction was 37.5 to 54.0 per cent, in summer it was 69.1 to 81.8 per cent and in autumn 65.3 to 68.5 per cent.

쥐 유선(乳腺)의 임신(姙娠), 필유(泌乳) 및 휴지기(休止期)에 있어서 조직계량학적변화(組織計量學的變化)는 다음과 같았다. 유선상피(乳腺上皮)의 발달(發達)은 임신(姙娠) 18일(日)에 있어서 분만시(分娩時)(100%로 했을 때)에 비(比)하여 42%에 달(達)하였다. 이유후(離乳後) 10일(日)에 있어서 유선(乳腺)의 지방(脂肪), 기질(基質) 및 상피(上皮)의 양적(量的)인 비율(比率)은 임신(姙娠) 10일(日)에 있어서와 비슷하였다. 임신(姙娠), 필유(泌乳) 및 휴지기중(休止期中)의 주요(主要) 구성성분(構成成分)의 변화(變化)는 지방(脂肪) 및 상피(上皮)에 있었고 기질(基質)은 관계치 않았다.