540 



Capt. J. Hammond. 



Eabbit 2. — Foetuses (3 and 5) removed on the 13th day after coitus. Milk 

 expressed on the 21st day. Killed on the 27th day. Placentae attached to 

 the uterine wall, three well developed, but the remainder showing signs of 

 atrophy. Mammary glands not thickened. 



Eabbit 3. — Foetuses (4 and 5) removed on the 13th day after coitus. No 

 milk on the 15th day. Fur pulled out and nest made on the 31st day. 

 Killed on 32nd day, when milk was squeezed from nipples. Seven placentae 

 found loose in body cavity. Mammary glands not thickened. 



Eabbit 4. — Foetuses (3 and 5) removed on the 15th day after coitus. 

 Making nest on the 20th day. Killed on the 22nd day, when milky fluid 

 was expressed from nipples. Seven placentas found loose in body cavity. 

 Mammary glands not thickened. 



Eabbit 5. — Foetuses (3 and 5) removed on the 15th day after coitus. 

 Making nest on the 20th day. Colostrum expressed on the 23rd day, Killed 

 on the 30th day. Three atrophic placentae attached to uterus, and four 

 placentas found loose in the body cavity. Mammary glands not thickened. 



Eabbit 6. — Foetuses (5 and 5) removed on the 15th day after coitus. 

 Milk expressed on the 19th day. Killed on the 28th day. Three atrophic 

 placentae attached to the uterus and six free in the body cavity. Mammary 

 glands not thickened. 



It is concluded from these experiments that the foetus is a necessary factor 

 in causing the secondary growth changes in the mammary gland. In these 

 cases the placentae were retained and, in some of the animals, in a fresh 

 condition. The results confirm those of Biedl and Koenigstein,* who found 

 that implantation of placentae into non-pregnant rabbits was without effect on 

 mammary secretion, but that implantation of the foetus resulted in the growth 

 of the gland and the secretion of milk. 



There are several facts, however, which indicate that the action of the 

 foetus on the mammary gland is not a direct one. Halbanf has pointed out 

 that the origin of the stimulus which causes milk secretion must be situated 

 ■outside the foetus, since the act of parturition sometimes results not only in 

 tho secretion of milk by the mother but also by the foetus — the so-called 

 " witch's milk." 



Moreover, many cases are known in which a woman has produced a healthy, 

 vigorous child, and yet the mammary glands secreted very little milk. Also, 

 as O'DonoghueJ has pointed out, milk is secreted in the rabbit several days 



* Biedl and Koenigstein, 'Zeits. f. Exp. Path. u. Therap.,' vol. 8 (1911). 



t Halban, ' Arch. f. Gynaek.,' vol. 72 (1905). 



| O'Donoghue, 'Quart. Journ. Micro. Science,' vol. 57 (1911). 



