190G.] Growth and Activity of the Mammary Glands. 515 



B received the unboiled extract of 55 placentae. It was killed on November 2. 

 Mammary glands unchanged ; uterus slightly congested. 



IV. Injection of Foetus with or without Placenta and Uterine Mucous Membrane. 



The first three experiments on this point were also fruitless so far as regards any 

 change in the mammary glands. In these cases the rabbits received from five to seven 

 injections of extract of foetus. The following experiments, therefore, were conducted 

 for a longer period of time, and a much larger number of injections were given, and 

 in these positive results were obtained. 



Experiment 9. February 8, 1905. A rabbit, eight mouths old, which had been in the 

 laboratory since it was a fortnight old virgin received, sitbcutaneously, extracts made 

 by rubbing up foetuses and their placenta; with sand, extracting with normal saline, 

 centrifuging, and filtering through a Berkefeld. The injections were made as follows : 



February 8. Half the extract of 7 foetuses at the 20th day. 



9. 7 20th 



10. 4 foetuses at the 22ud day. 



11. 5 14th 



13. -4 14th 



14. 3 22nd 



15. 4 20th 



16. Half the extract of 8 fwtuses at the 20th day. 



171 8 20th 



18. 6 foetuses at the 19th day. 



20. 5 14th 



21. Half extract of viscera of 6 foetuses at the 25th day. 



22.- 6 25th 



23. Viscera of 7 foetuses at the 20th day. 



24. 4 24th 



The rabbit was killed on February 25. There was marked hypertrophy of the 

 mammary glands, which were surrounded with a certain amount of thud remaining from 

 the subcutaneous injections. The ovaries were large, the uterus congested, and the vulva 

 showed signs of heat. On microscopic examination there was found to be marked hyper- 

 trophy of ducts, which were branching and lined with many layers of cells. The mitotic 

 figures were numerous. Specimens of the mammary glands from this rabbit were shown 

 at the meeting of the Physiological Society at University College in March, 1905. 



Experiment 10. February 27, 1905. Intraperitoneal injection of press-juice of the 

 viscera of fo?tuses, together with placentas and uterine mucous membrane. 



A virgin rabbit received the following injections : 



February 27. 8 foetuses, etc., at 24th day. 



28. Half of 9 foetuses, etc., at 24th day. 

 March 1. 9 24th 



2. 8 foetuses, etc., at 25th day. 



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 6. 6 



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