242 



WILLIAM LAWRENCE TOWER. 



OJ 











M 



C ' 



which the capacity to hold the water in the hibernating genera- 

 tion has developed. Tests of the capacity to hold the water 

 in the tissues against desiccation have been made in the different 

 series of experiments, with rather striking results. 



These tests are made by taking about equal weights of one 

 of the Tucson cultures from the generation that is hibernating, 

 and from the cultures at Chicago, enclosing them in small 



Duration of survival of T. 99 11.5 



120 

 no 



IOO 



90 

 80 

 70 

 60 

 50 

 40 

 30 



20 

 10 



Duration of survival of C. 100 



3-S 



10 II 12 13 14 15 



D 



a 

 a 



a 

 6 



rt 



*O 





 O 



M 



ca 



u 

 'w 

 D 

 d 



ai 



ffl 



2 



*f* ^^ I, 



-% 



B 



Time in days. 

 Weighings made at 12 hours intervals. 



FIG. 2. 



wire cloth containers, the two, then subjected to intense desicca- 

 tion by the passage of a current of dehydrated air at a uniform 

 rate through the materials until death has resulted, and the 

 materials attained a uniform dry weight, weighings being taken 

 every twelve hours. 



These tests show that the Tucson materials, especially after 



