8o 



SENESCENCE AND REJUVENESCENCE 



vertical column gives in hours and minutes the length of time in 

 cyanide at each examination; the second gives the serial number 

 of each lot, and the five columns headed by Roman numerals under 

 " Stages" give the number of animals of each lot in each stage of 

 disintegration at each examination. In this case Lot i consists 

 of ten young worms, four to five millimeters in length, and Lot 2 



Stages and 

 their values 



a c 



Hours o 



FIG. 3. Planar la dorotocephala: susceptibility curves of young (ab} and old 

 (cd} animals in KCN o.ooi mol. Graphic presentation of the data of Table I. The 

 vertical intervals represent the arbitrary numerical values of the average disintegra- 

 tion stages, the horizontal intervals half-hour periods. 



of ten old worms fifteen to sixteen millimeters in length, both from 

 the same stock. 



The table shows that in the young worms of Lot i disintegration 

 begins earlier and proceeds more rapidly than in the old worms of 

 Lot 2. The young worms have all reached Stage V after two and 

 one-half hours in cyanide, while none of the old worms have reached 

 this stage at this time and all of them reach it only after five and 



