ADAPTATION OF I'AKAM.E( IA TO ENVIRONMENTS. 



they had been previously subjected but a medium which was 

 from - \ ral days to several w<-k- old. 



I'nder these conditions this culture of P. candatum now 

 Hoiiri-hc-, and it is continued by isolating a few cells every 

 feu \\rrks and inoculating with them another >mall flask of old 

 infusion. I nder these conditions it is impossible, of course, to 

 It !< inline with accuracy the rate of division or the number ol 

 j< IK r.ni'.n- attained to date, but the organi-m-. are apparently 

 in .1 normal physiological condition. H<\\e\er. it i> still im- 



100 



200 



300 



400 



Fie, _. r.uimtriium faiiJatum (Culture X.). Graph of the rate of reproduc- 

 tion I>T tin- i. generations (May 14. 1910. to June i. i 



1 In of division of the four lines of the cultun i- .1 d for 



l>iii..'l- ,.i on :. The figures 100, 200. etc.. represent & -m -t.iti..n- ;uil are 



IM-|I>\V tin- iiniiitlis in which they were attaim-'l. 



]Hi^-,iliU- to keep them alive on slides in tin- n-^ulaiion li\e 

 <! trc-h ruhure medium, which has pr.-M-d so highly fax 

 ii 'i the nnn-liii culture. 



\n\\ tin- i|iie-iin arises: Have the cells foniu-aied in the 

 larger \-olume <-t medium and so been "rejuvenated." ^ince I 

 have been unable to isolate the animals each day. I cannot pr< 



thai nmiiiuaiii'ii ha- not occurred, for it i- ]>'>-- iMe thai one Of a 



fe\\ pairs ha\e ennjugaifil unobserved ami ha\e given HM- to the 



