Immunity of Lower Organisms to Ethyl Alcohol 577 



gave clear evidence of immunity when tested by either of the meth- 

 ods. This will be seen from the two experiments which follow. 



The first of these, in which F was tested for an increased resist- 

 ance to a fatal dose, was made in the following way: 



Into each of two dishes, designated respectively as A and C, 

 was put 5 cc. of a natural culture medium, containing twenty 

 normal Stentors. To A was then slowly added i cc. of 6 per cent 

 alcohol, forming a i per cent acclimatizing medium. After a 

 few days the animals from A (acclimatized to i per cent alcohol) 

 and from C (control) were tested to a 6 per cent concentration — 

 each experiment consisting of a drop (either of A or of C, contain- 

 ing a single Stentor) added to i cc. of 6 per cent alcohol. The 

 death-point was taken as the instant at which ciliary movement 

 ceased.*^ The period of resistance — the number of seconds that 

 the organism survived — ^was marked in seconds. 



The experiment shows the following comparative results : 



Experiment I. 



RESISTANCE OF STENTOR OF TYPE F TO 6 PER CENT ALCOHOL AFTER LIVING 4 DAYS IN I PER CENT ALCOHOL 



A Four Day!, in I Per Cent Alcohol C Control Animals 



Seconds Seconds 



Exp. I cilia stop 150 Exp. i cilia stop icxj 



2 cilia stop 130 2 cilia stop 145 



3 cilia stop 300 3 cilia stop 120 



4 cilia stop 720 4 cilia stop 120 



5 cilia stop 220 5 cilia stop 275 



6 cilia stop 300 6 cilia stop 225 



7 cilia stop 410 7 cilia stop 150 



8 cilia stop 160 8 cilia stop 115 



9 cilia stop 350 9 cilia stop 225 



10 cilia stop 270 10 cilia stop 150 



Average resistance = 301 Average resistance = 162.5 



Thus the animals which had been kept for a brief time in a i per 

 cent solution resisted 6 per cent alcohol on the average 301 



'2 It will be observed from following work that the cilia in different regions of the body show different 

 powers of resistance, depending upon the substance used. Thus, in the case of ethyl alcohol the per- 

 istomal cilia are usually active longest, while in glycerine the body cilia continue long after the peristome 

 is lost. 



