298 REPORTS ON THE STATE OF SCIENCE. 



not infrequently proved possible of accomplishment when mice of not 

 more than six or seven weeks old are used. In view of the further fact 

 that fanciers are agreed that the mouse is incapable of reproduction 

 before the age of three months, while six months is generally stated to 

 be the earliest age at which these animals should be mated in order to 

 ensure healthy offspring, it would appean #rab the greatest measure of 

 success in experimental implantation of cancer in this animal is obtain- 

 able only during the period of life antecedent to full or even commencing 

 activity of the reproductive functions. On the other hand, implanta- 

 tion of cancer material from one mouse to another is least likely to be 

 attended by success when the recipient is of an age at which these 

 functions have attained the stage of full activity. 



For these and other reasons it appeared desirable to investigate the 

 question as to whether any of the products of the reproductive glands — 

 presumably given off, under normal circumstances, in the Torm of an 

 internal secretion — can be shown experimentally to influence, in one or 

 another direction, the development of cancer as witnessed when this 

 disease is experimentally produced in the mouse. For the prosecution 

 of this investigation facilities have been most kindly afforded by the 

 Executive Committee and the Director (Dr. Bashford) of the Imperial 

 Cancer Eesearch Fund, and the Committee is much indebted to them 

 for a generous supply of material. 



Although at the present time but little doubt exists as to the produc- 

 tion of an internal secretion by the testes and ovaries, practically nothing 

 is known of its nature and composition. It has, however, been sug- 

 gested that its main constituent is in all probability derived from meta- 

 bolism of nucleo-proteids which are present to so considerable an extent 

 in the tissues of the reproductive glands. Professor von Poehl, of St. 

 Petersburg, and others have, indeed, claimed that spermin, a crystallis- 

 able substance which has been isolated from the testes, prostate, ovaries, 

 and in less amount from certain other organs and tissues, constitutes 

 the essential principle in question. For the purposes of the present 

 investigation, therefore, it appeared desirable, in the first instance, to 

 make use of this substance (of which Dr. von Poehl, the successor of 

 the late Professor von Poehl, kindly provided supplies), employing, in 

 addition, freshly prepared emulsions of mouse testes, extracts of dried 

 and powdered testes freed from nucleo-proteid, boiled watery extracts 

 of the testicle of various animals, and a solution of nucleinic acid of 

 orchitic origin. In every instance the action of all these various sub- 

 stances was tested on the mouse by hypodermic injection, while fresh 

 emulsion of testes and solutions of nucleinic acid were also administered 

 internally by a method of experimental feeding devised for the purpose. 

 For each series of experiments a number of mice were employed 

 which had been inoculated with cancer material by a member of the 

 staff of the Imperial Cancer Eesearch Laboratories, from ten days to 

 three weeks previously, by which time most of the animals had developed 

 tumours, sometimes of considerable size, at the site of operation. The 

 precise area of the resulting tumours in each animal is recorded on 

 charts by one of the laboratory attendants ten days after implantation, 

 and subsequently at weekly intervals. In every experiment one lot of 

 inoculated mice was set aside as a control. Each series of experiments 



