326 CCL ALUREGE 
individuality on the basis of tissue implants of any sort, such as 
that made by Loeb, must take careful account of the age and 
sex of individuals as well as of the particular tissue used and of 
the genetic factors involved in the races and individuals used. 
In conclusion, I wish to acknowledge my indebtedness to my 
assistants, the Misses Johnson, Jones, and Newman for their 
interest and accuracy in completing with me the tedious work of 
observing and recording the mice. 
LITERATURE CITED 
Litre, C. C., anp Tyzzer, E. HE. 1916 Jour. Med. Research, vol. 33, p. 393. 
Lors, L. 1920 Am. Nat., vol. 54, p. 45. 
1920 Am. Nat., vol. 54, p. 55. 
Mourpny, J. B. 1912 Jour. A. M. A., vol. 59, p. 874. 
1913 Jour. Exp. Med., vol. 17, p. 482. 
Tyzzmr, E. E. 1915 Jour. Med. Research, vol. 32, p. 331. 
Tyzzer, E. E., anp Littnn, C. C. 1916 Jour. Cancer Research, vol. 1, p. 387. 
