7J4 INTERNAL SECRETION 



^J I I 



of virgin rabbits, with the object of obtaining hypertrophy of 

 the mammary glands. In six cases they actually succeeded in 

 producing a certain degree of hyperplasia with foetal extract, but 

 the experiments with extracts of placenta, ovary, and uterine 

 mucous membrane were negative in result. In one case, the 

 injection of the watery extract of 160 foetuses was followed by the 

 formation of secreting acini at the periphery of the mammary 

 gland. 



The conclusiveness of Starling's experiments is disputed by 

 Halban, who regards the number as insufficient to establish proof ; 

 he also points to the possibility that the changes in the mammary 

 gland observed after injection of foetal extract were in reality 

 symptoms of rut. This pronouncement of Halban 's induced me 

 to submit the question to further experimental test, the experi- 

 ments being undertaken with the aid of Dr. R. Konigstein. 



While our experiments were still in progress a communication 

 of Foa's appeared, in which he confirmed the findings of Starling 

 and Claypon, and supplemented them with the statement that the 

 action of the hormone is not confined to the species from which it 

 is derived. Thirty-five injections of an extract obtained from 

 fresh foetuses from cows produced swelling of the mamma? in a 

 virgin rabbit, and on isolated occasions a secretion resembling 

 milk was observed. 



Our experiments, which will be fully described in another 

 place, showed that neither the repeated intraperitoneal injection 

 of placental extract, nor the implantation of fresh placentas of 

 rabbits in the abdominal cavity, produced histological changes of 

 any kind in the mammary glands of virgin rabbits. There was, 

 however, a more or less marked development of the mammary 

 glands of all virgin animals treated by means of intraperitoneal 

 injection of embryonal extract or by the intraperitoneal implanta- 

 tion of one or more embryo rabbits. Numerous glandular ducts 

 appeared, frequently with well marked branches, or, at the least, 

 formation of buds ; the lumen of the ducts became enlarged, con- 

 taining in some instances a cellular secretion ; the number of 

 epithelial layers usually increased; in nearly all cases there was 

 hyperaemia ; acini formation was isolated onlyj the excretory 

 ducts were enlarged and much more fully developed. The 

 intensity of these changes was in direct ratio to the amount of 

 extract injected or of material implanted. The glandular hyper- 

 trophy was more marked in animals treated by means of injection 

 than in those in which embryos were implanted. 



The results of these experiments seem to show that, contrary 

 to the view expressed by Halban, the foetus is the source of origin 

 of the hormone which stimulates the growth of the mammary 

 glands. 



K. Basch has recently published a work which is chiefly 

 concerned with the experimental investigation of those cases 



