Gamma-globulin was separated from the anti-PMSG immuno rabbit serum by using diethylaminoethylcellulose anion exchanger. The studies of immunoelectrophoretic analysis and treatment of 2-mercaptoethanol show that the major constituent of the isolated antibody activity was IgG (7S, γ2) type γ-globulin.

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馬の錠剤化凍結精液による授精試験を行ない,受胎例を得た。
膠様物を除去した馬精液を,卵黄トリス緩衝ブドウ糖液で2倍に予備希釈を行なった後,800g,20分間の遠沈を行ない,原精液の量に濃縮した。
濃縮精液を5%の卵黄,5.5%のグリセリン(終末濃度3.6%)を含む卵黄-トリス緩衝ブドウ糖液で3倍に希釈,5°Cまで徐々に冷却し,グリセリン平衡2~3時間の後,その0.3mlをドライアイス上に滴下して錠剤化凍結した。
保存はドライァイス粉末中で行ない,授精は30錠の精液を30~35°Cに保った融解液中で融解した直後に実施した。
凍結融解後の精子生存率は,かなり良好で,授精試験の結果は,7頭中2頭が受胎し,正常な雌雄各1頭を分娩した。
以上の事実は,低濃度のグリセリンで,しかも急速な冷凍を行なう錠剤化凍結法が馬精液にも効果的であること示唆していると考えられる。

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馬の錠剤化凍結精液において,精子生存率におよぼすグリセリン平衡,グリセリン濃度,糖の影響を検討し,また錠剤化凍結精液による野外授精試験を実施して以下の成績を得た。
1)グリセリン濃度
グリセリン1.75,3.5,7.0%の濃度の間の凍融後の精子生存率では,融解液を添加した場合3.5%の濃度が良好であった。
2)グリセリン平衡時間
、グリセリン平衡にともなう凍融後の精子生存率の推移は,糖の種類,融解液の有無によって差異が認められる。融解液を添加しない場合,凍融後の精子生存率は平衡時間の経過にともなって低下するが,融解液添加の場合シヨ糖では顕著でなく,ラフィノース-グリセリン液では逆に5時間までは改善される傾向が認められる。グリセリンを含まないものでは,シヨ糖,ラフイノースとも融解液の有無に関係なく,平衡時間の経過にともない凍融後の精子生存率は低下した。
3)糖の種類
シヨ糖,ラフィノースの比較では,5時間以上の平衡でラフィノースが優っていた。
4)融解液の影響
いわゆる緩衝糖液加牛乳を融解液として使用した場合,凍融後の精子生存率ならびに加温顕微鏡下における精子生存時間が延長される。
5)受胎成績
1965年に実施した錠剤化凍結精液による授精試験において42頭に授精して12頭に受胎を見た。供用雄馬3頭の受胎率はそれぞれ,47. 3, 26. 7, 12.5%で非常に大きな個体差が認められた。最も低い受胎率を示した雄馬の精液はドライアイス中で凍結したものを汽車輸送したほかは他と条件は変らない。
受胎例における授精の条件は,精液の保存日数1~28日,精子生存率は30~40%,1回の注入精液数は10~30で,一発情当りの注入回数は1~3回であった。
しかし同じ条件で不受胎に終った例もかなりあって,上記各種の要因と受胎との明らかな関係は見出し得なかった。
注入対象の雌馬の注入適期,排卵の有無を把握できなかった試験条件も考慮すると,前記雄馬の個体差のほかに,雌馬の条件がこの受胎成績にかなり大きな影響をおよぼしているように考えられる。

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In the previous report, we investigated the effects of intrauteine injection of a viscous gel-like substance on the life span of the corpus luteum in the cow. The intrauterine treatment at early luteal phase caused an early regression of the corpus luteum and shortened the cycle length significantly. On the contrary, the treatment at late luteal phase delayed the regression of the corpus luteum and lengthened the cycle. The purpose of the present experiments is to investigate the relation between the irritating effects of the intrauterine injection of the viscous gel-like substance on the endometrium and the modification of the cycle length in the cow. The viscous gel-like substance was “Gelceptor F” (G) which was same as in the previous report.
Three experiments were performed to determine 1) the retention of G in the uterus of the treated cow, 2) the irritating effects of the treatment on the bovine endometrium and 3) the effective period of the uterine irritation for modifying the cycle length of the cow.
The cows used in the present experiments were almost same as in the previous report. Dose of G was 42-137 gm. per injection. The day on which ovulation occured was considered as day 0 of the cycle. The results obtained were as follows.
1) The retention of G in the uterus of the treated cow. The retention of in G the uterus was verified by rectal palpation on 32 cycles of 9 cows in which intrauterine injections of G had been performed 1 to 5 times. The results are shown in Table 1. In only 3 of 16 cases treated during postestrus and in early luteal phase, liquid contents in the uterus were palpable for a few days after the treatment. After treatment during functional luteal phase and late luteal phase, uterine contents were palpable for 2 to 3 days in 10 of 16 cases. In 5 of the latter cases the uterus was swollen as in the case of pyometra or pregnancy. However, the swollen uterus involuted rapidly as the corpus luteum began to degenerate. From these results it was concluded that the retention of G in the uterus depended upon the stage at which the intrauterine injection was performed, the retention period being longer in animals treated at postestrus-early luteal phase.
2) The irritating effects of the treatment on the bovine endometrium.
A. Responses of cervical mucus following the treatment.: On 20 estrous cycles included in experiment 1, cervical mucus samples collected before and after the treatment were examined macroscopically and microscopically. The microscopical examination was performed on the mucus smear stained with Giemsa. The results are shown in Table 2. For 1 to 3 days after the treatment, the cervical mucus became cloudy or greyish white and a large number of neutrophil leucocytes and epithelial cells and a small number of eosinophil leucocytes appeared in most of the cases. However, cervical mucus became clear again in the following estrous period.
B. Effects of the treatment on the endometrium.: The endometrium of seven beef cows slaughtered 1 to 9 days after the intrauterine treatment was examined macroscopically. In an additional 5 cases, the endometrium at the first post-treatment estrus was also examined histologically by endometrial biopsy. The results are shown in Table 3. In five of the seven animals, 105 to 330 gm. of brownish liquid were recovered from the uterine cavity. The volume of the uterine contents recovered was greater than the quantity of G injected. The surface of the endometrium was rough and brownish in colour in six of the animals. Marked edema was also observed in the endometrium of five animals. Endometritis was found four of the seven animals. However, the endometritis was limited to the surface area of the endometrium only. The uterine glands appeared normal in all cases. In five animals in which endometrial biopsies were carried out at the post-treatment estrous period, endometritis was not found in any of them.

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In order to elucidate the mechanism of the initiation of parturition, it seems very suggestive to investigate how the parturition takes place in superimplanting rats.
Superimplanting rats were prepared, mostly based on the method of Yoshinaga²⁾, as follows ; into the adipose tissue of mesometrium of a lactating pregnant rat with 6 pups, a small amount of estradiol was locally administered on the 5 th day of the pregnancy and pups were removed on the 9 th day. The mother was laparotomized on the 20 th day, and the fetuses were distinguished into the younger and the elder one(s) by the size of uterine swellings, and the number and location were recorded. The mother was continuously observed for the parturition thereafer.
In spite of the above mentioned treatment, there were cases in which only the elder or the younger fetus(es) was conceived. Judging from the day of parturition (shown at the upper column of Fig. 1) and the body weight in these cases, it was assumed that the implantation of the elder was about 5 day earlier than that of the younger.
Two types of parturition were observed in these superimplanting rats. The first; the elder(s) was delivered alive and at the same time the younger(s) was born in premature state. The second; the youngers were delivered normally at full term, and the elder(s) delayed in parturition and was dead in uterus or delivered dead together with the youngers. In other words, the parturition took place only once but never twice for the elder(s) and for the younger(s) with a few days interval.
Csapo¹⁾ has stated that the activity of the uterus of a pregnant animal is supressed more by proge-stin locally secreted from a placenta than by that in systemic circulation, and has concluded that the activity of the pregnant uterus is controlled by the ratio of the uterine volume and the local concen-tration of progestin in uterine tissue. If his theory applied on our experiment, the parturition should have independently taken place at the uterine horn having the youngers only, whether the elder(s) in the other horn was delivered or not. In such cases, however, when the elders were delivered, the parturition always occurred simultaneously to the contralateral horn in which only the youngers were implanted.
The number of the elders exceeding three, the first type of parturition mostly took place, although the day of parturition always delayed for about two days, and the second type mostly took place when the number was one. When the number was two, the both types occurred, and it seemed to have a close relation with the number of the youngers whether the first or the second type took place. From these facts, though very complex mechanism was anticipated for the induction of parturition, it is, assumed that the uterine volume, as Csapo suggested, may be one of the important factors which bring about parturition.

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