November 28, 1913] 



SCIENCE 



785 



On July 15, 1912, over two years after the 

 operation, the grafted mother was noted as 

 still having well-developed mammse and geni- 

 talia, as if she possessed functional ovarian 

 tissue. On November 25, 1912, she died and 

 there was found post mortem a large cyst in 

 the uterus on the right side, and on the left 

 side at the site of the graft a large ovarian 

 mass, doubtless the source of the functional 

 ova liberated during the two years previous. 

 No microscopic study of this tissue was made, 

 as it was already in an advanced stage of de- 

 composition when observed. 



To summarize the record, two of the five 

 young were colored, and three were albinos. 

 Both of the colored young were cinnamon, like 

 the graft producer, rather than brown like the 

 foster mother. As regards the albinos, it re- 

 mained to ascertain whether they were poten- 

 tial cinnam,ons or potential hrowns. This re- 

 quired a breeding test which we were able to 

 complete in the case of one of the three only. 

 This animal, a male, when mated with brown 

 females, produced two brown and one cinna- 

 mon young, showing that he was potentially 

 a cinnamon though heterozygous for brovm. 

 He had accordingly inherited cinnamon from 

 his foster mother, or rather from the graft 

 which she contained, for his albino father did 

 not transmit cinnamon. This could be in- 

 ferred from the fact that the brown-eyed cream 

 ancestors of the albino father were known not 

 to transmit cinnamon, but it was further es- 

 tablished by mating him with brovm females, 

 by which he produced five brown young and 

 two albinos but no cinnamons. 



If, as stated, the albino father. No. 2,420, 

 did not transmit cinnamon, then his cinnamon 

 offspring, or potential cinnamon albino off- 

 spring, by the grafted brown mother, would 

 have to be merely heterozygous in cinnamon. 

 Therefore, we should expect only half of their 

 young to be cinnamon, when they were mated 

 with brown animals. The potential cinnamon 

 albino, as already noted, when so mated, had 

 one cinnamon and two brown young. 



Finally, the cinnamon female. No. 2,986 

 borne by the grafted mother, was mated with 



her albino father {potentially a brown-eyed 

 cream, since his parents were of that recessive 

 variety). She produced eight young, of 

 which five were brown-eyed creams, two al- 

 binos and one a cinnamon ; expectation 2:4:1. 

 The production of a cinnamon young one in 

 this mating shows that the cinnamon animal 

 not only inherited but also transmitted the 

 cinnamon character, as if her mother had been 

 a cinnamon animal instead of a cinnamon 

 graft in a brown animal. The sojourn and 

 development, in the body of a brown animal, 

 of an ovary taken from a cinnamon animal 

 does not seem to have altered in any respect 

 the initial genetic potentialities of the germi- 

 nal substance. 



These three cases form a substantial body 

 of evidence in favor of the view originally ad- 

 vanced by Weismann that in the higher ani- 

 mals germinal substance and body are physio- 

 logically distinct, and that the genetic 

 potentialities of the latter are not subject to 

 modification through somatic influence. 



It may be of interest to note that in our 

 entire work 141 female guinea-pigs were 

 grafted with foreign ovaries. Of these about 

 100 were mated with males long enough to give 

 dSfinite indications of their ability to pro- 

 duce young. Only 3, as noted, actually 

 produced young, but in 7 others engrafted 

 ovarian tissue persisted for many months 

 and was demonstrated post mortem. In 11 

 cases ovarian tissue was regenerated at the 

 original ovarian site and in 3 of these cases 

 young were produced having the genetic char- 

 acters of the mother, but never those of the 

 graft. In 87 cases no ovarian tissue what- 

 ever was found post mortem, the castration 

 having been completely successful but the 

 transplanted ovaries having failed to persist 

 for any length of time in the foreign body. 



The small percentage of successful trans- 

 plantations indicates that the method is not 

 likely to be useful practically in the domestic 

 animals or man unless some means can be dis- 

 covered for increasing the tolerance of the 

 body to foreign tissues. We have considered 

 in this connection the possibility of increas- 

 ing this tolerance by holding the tissue to be 



