l82 PERFORMANCE OF THE EXPERIMENT 







in many places, and here part of the liquid became 

 enclosed by capillary action, thus forming a kind of 

 communication between the contents of the tube- and 

 the liquid outside. From these observations it 

 follows, that the toluol should never be introduced 

 before the dialysing tube has previously been im- 

 mersed in the 20 c.c. of water, in which case the 

 quantity of toluol added can be accurately controlled, 

 and care can be taken that both the inner and outer 

 surfaces of the tubes shall project at least 0*5 c.c. 

 over the toluol layer. Moreover, only wide-mouthed 

 Erlenmeyer flasks should be used. 



Then the flasks are placed in an incubator at a 

 temperature of 37 C. At a higher temperature the 

 ferments would be destroyed, and at a lower tem- 

 perature the decomposition would be too slow. 



After about sixteen hours the experiment is stopped. 

 A thick layer of toluol must still be found upon the 

 contents of the tubes, as well as on the surrounding 

 liquid, at the end of the experiment. The Erlenmeyer 

 flasks, carefully numbered, are best arranged in no 

 special order. Then the tubes are taken out of the 

 flasks, and placed, right up to the end of the experi- 

 ment, into empty Erlenmeyer flasks. In withdraw- 

 ing the tubes one at the same time effects a uniform 

 mixing o f the dialysate. Particular care must be taken 

 to avoid a source of error that often arises at this 

 point, which is, that if the flask has been supplied 



