The Action of Animal Extracts on Milk Secretion. 17 



Until quite recently nothing had been ascertained regarding the influence 

 of animal extracts upon milk secretion. But in a type-written notice 

 inserted into a pamphlet on " Internal Secretions," by Dr. Isaac Ott, of 

 Philadelphia, and dated October 28, 1910, the brief statement is made that 

 " infundibulin is a rapid and powerful galactagogue."* This pamphlet 

 came into our hands on November 20, and the statement in question 

 furnished the starting point of our investigations. 



The animal extracts which we have investigated are numerous, and 

 include not only extracts of both parts of the pituitary body, but also 

 extracts of placenta,f uterus in process of involution, mammary gland, 

 duodenum, liver, spleen,! kidney, thyroid, ovary, testicle, thymus, and 

 suprarenal capsules. In the ovary we investigated separately the ovarian 

 substance proper and the substance of the corpora lutea. And in view 

 of the growth of mammary gland substance which was found by 

 Miss Lane-Claypon and Prof. Starling§ to be produced in the (virgin) 

 rabbit by hypodermic injections of extract of rabbit-foetuses, we also tried 

 the effect on the secretion of the mammary gland (of the cat) of intra- 

 venous injection of extract of cat-foetuses, with, however, a negative 

 result. The most constant positive results which we have obtained have 

 been those resulting from extracts of the posterior lobe of the pituitary 

 body (of the ox) and of corpus luteum (of the sheep). Of these two 

 materials that contained in the posterior lobe of the pituitary body is the 

 more active. The accompanying curve (fig. 1) exhibits the effect produced 

 by intravenous injection of a small amount of this extract. Prior to the 

 injection no milk was passing from the gland ; indeed, in the absence of a 

 special stimulus the secretion almost always remains in abeyance. But 

 within 20 seconds of the injection, drops of milk began to fall fast from the 

 tube, the end of which was little, if at all, below the level of the gland with 

 which it was connected, so that the flow was not assisted by suction, but 

 must have been the result of the vis a tergo of the secretion. The effect 



* "Infundibulin " appears to be a proprietary article and is described by Ott (p. 57) as 

 "a 20-per cent, extract of the pituitary." But probably, as the name implies, the 

 infundibular part of the gland is alone used in its preparation. 



t Lederer and Pribram (" Eeport of Internat. Physiol. Congress, Vienna," ' Zentralbl. 

 f. Physiol.,' 1910, vol. 24, p. 817) state that they have obtained increase of milk secretion 

 in the goat as the result of intravenous injection of unboiled extract of placenta, but our 

 results with this extract have so far been negative (in the cat and dog). 



% In investigating the action of spleen extracts we have incidentally found that such 

 extracts may produce marked diuresis, without either rise of blood-pressure (in point of 

 fact the blood-pressure falls) or increase of kidney volume. The diuresis must therefore 

 be caused by a direct stimulating action upon the secreting cells of the kidney. 



§ ' Eoy. Soc. Proc.,' B, 1906, vol. 77. 



VOL. LXXXIV. — B. C 



