44 Dr. J. A. Murray. Cancerous [Mar. 22,, 



Table I. (October 24, 1910.) Female Mice. 



Age (months) ... 



3 



6 



9 



-12 



-15 



-18 



-21 



24 



Over 

 24 



Total. 



No tumour — 

















9 







Dead 



= 



= 



79 



85 



63 



56 



41 



37 



1 



8 



24 



- 



Tumour mice — 







5 



1 

 11 



2 

 16 



26 



2 

 10 



3 

 5 





















Total 







100 



104 



88 



93 



69 



55 



53 



562 



Per cent, of mam- 







5-0 



10 6 



18-2 



28 -0 



14 -5 



14-0 



9-4 



14-4 



barely twice that found in mice under nine months old. Similar figures 

 for the human female give a corresponding curve. 



Tables II and III were made after a preliminary distribution of the 

 mice in groups, according as the first cancerous ancestor occurred in the- 

 1st, 2nd, 3rd,... ascending generation, had shown that the majority of the 

 cases of cancer occurred in mice in which either the mother, or a grand- 

 mother, or all three, developed cancer. 



Table II. (24th October, 1910.) Female Mice of Ptecent Cancerous 



Ancestry. (Mother, one or both grandmothers, or all three cancerous.) 



Age (months) ... 



0-3 



-6 



-9 



-12 



-15 



-18 



-21 



-24 



Over 

 24 



Total. 



No tumour — 

 Lvving 







9 



*7 



6 



8 



7 



4 



6 





Dead 







49 



48 



1 



39 



28 



22 

 1 



20 



18 

 1 





Tumour mice — 

 Organs other than 









2 



2 







Mamma 







4 



7 



15 



18 



10 



5 



3 





















Total 







62 



63 



62 



56 



40 



29 



28 



340 



















Per cent, of mam- 







6-5 



u-l 



24 -2 



32 -1 



25 -0 



17 -2 



10 -7 



18 -2 



Table II shows the proportions in which mice of recent cancerous- 

 ancestry, in this limited sense, died of cancer at the different age-periods.. 

 Table III is to be compared with Table II, and gives the same distribu- 



