INFLUENCE OF TEMPERATURE 



53 



The fact that it was one of the largest drops which 

 showed this long continued streaming is a confirmation of 

 a phenomenon which was also plainly seen in studying 

 the smaller drops. Very minute drops, consisting of only 

 relatively few alveoli, as often occur (see p. 19) in the 

 preparations, were never seen by me to pass into the 

 condition of streaming. Larger drops of perhaps 0'05 to 

 O'l nun. diameter usually showed very fair streaming 

 movements, which did not, however, last long, becoming 

 extinct after one or a few hours. Streamings of such long 

 continuance as have been mentioned above can only In- 

 observed in relatively large drops. The continuance of 

 the streaming stands therefore in direct relation to the 

 size of the drop, which harmonises well with the ex- 

 planation of the phenomena which we shall come to speak 

 of below. 



Influence of the Temperature, etc., on the Streamings 



If streaming drops are warmed on a Max Schultze's 

 hot stage up to 40 or 50 C., 1 it is easy to observe that 



Fig. 7. 



the streamings become much more quick and intense. 

 The same is true of their forward movements. In the same 

 way it may be observed how drops, which have already come 



1 The temperature is of course somewhat lower than is shown by the 



thermometer of the stage. 



