494 



SCIENCE 



[N. S. Vol. XLII. No. 1084 



good old times of thirty to fifty years ago when 

 (to quote Van Name), " a genus name had in 

 those days a real meaning to some others be- 

 sides the specialists in the class of animals to 

 which the genus happened to belong."' 



It is of course to be admitted that there are 

 good genera and bad genera ; that many groups 

 have been proposed as subgenera or even full 

 genera on inadequate grounds. Our synon- 

 ymies show what has been the fate of many of 

 them, and a like fate doubtless awaits many, 

 of recent origin, that have still to be weighed 

 in the balance of concurrent approval. As the 

 value of characters is a question that can not, 

 from its nature, be made the subject of rules, 

 as can questions of nomenclature, there seems 

 only the slow relief afforded by time and the 

 concurrent judgment of the specialists of each 

 field for the evils of too much subdivision. 



J. A. Allen 

 American Museum op Natural History, 

 New York 



the inheritance of cancer 

 In a short note^ I have recently commented 

 on Dr. Maud Slye's work on the inheritance 

 of cancer in mice. As to the credit due Dr. 

 Slye for her careful and laborious experi- 

 ments there can be no question. The impor- 

 tance of the subject, however, is such that it is 

 essential to understand the exact distinction 

 between the gathering of valuable data and the 

 interpretation of such data when gathered. 



The impression that Dr. Slye believed that 

 cancer was inherited in a Mendelian fashion 

 appears to have been more or less generally 

 created by her paper already mentioned. Any 

 one reading the editorial on her work in the 

 Journal of the American Medical Association 

 (Vol. 64, p. 1,326) can not fail to see that the 

 " great laws " of heredity mentioned there are 

 intended to be the Mendelian laws. The whole 

 subject is treated from that standpoint and the 

 optimism apparent must be considered to be 

 chiefly due to the belief that Dr. Slye's work is 

 an example of Mendelian inheritance. 



So too, any one reading the review of recent 



8 L. c, p. 187. 



1 Science, N. S., Vol. 42, pp. 218-219. 



work on cancer research by Dr. W. A. Dennis 

 in the St. Paul Medical Journal (Vol. 17, pp. 

 494-500) can see that he believes that 

 . . . the importance of her findings lies in the fact 

 that hereditary transmission ... is not fortuitous 

 but that, given parents of pure breed the results of 

 crossing may be confidently predicted. 



After outlining correctly the basic principles 

 of Mendelian inheritance, with the cross of 

 albino and gray mice as an example, Dennis 

 goes on to say: 



Maud Slye has taken advantage of this law 

 [Mendel's] of heredity to study the transmissibil- 

 ity or inheritability of cancer in mice. . . . These 

 studies [Slye's] have shown that the appearance and 

 numerical value of the albino character can be pre- 

 dicted with certainty from the manner of mating 

 the parents. The same is true of the whirling char- 

 acter of the Japanese waltzing mouse and the same 

 ha^ been demonstrated to he true of cancer.'^ 



The fact that no correction of the impression 

 so created was apparently forthcoming, and 

 the fact that the diagrams in Slye's paper 

 showing the inheritance of albinism repre- 

 sented a hitherto undescribed type of heredity 

 led me to comment on her work. 



Slye's recent denial of any desire or inten- 

 tion to apply a Mendelian interpretation to her 

 experimental results is an extremely important 

 postscript to her paper since it makes it vir- 

 tually impossible to expect the exact numerical 

 predictions in crosses which her reviewers have 

 believed could be made. 



Further than this, Slye's beliefs as to the 

 inheritance of albinism are, as I have stated 

 before, at sharp variance with the experimental 

 results of Castle, Allen, Bateson, Durham, 

 Cuenot, Plate, Davenport and others. The 

 suggestion made by Slye^ that the utilization 

 of wild grays rather than " artificial labora- 

 tory " grays places her work in a position dif- 

 ferent from that of these other investigators is 

 not significant, for I have repeatedly used wild 

 grays in my crosses and have found that their 

 hybrids obey Mendel's law in respect to the 

 color characters which they inherit. 



1 have suggested that Dr. Slye's data show- 



2 Italics mine. 



3 Science, N. S., Vol. 42, pp. 246-248. 



