WARMTH ON WHITE CORPUSCLES. 49 



(Fig. 13, 6, b'\ is allowed to pass into the moist 

 chamber, a precipitate of one of the constituents of 

 the stroma (probably paraglobulin) occurs around 

 the nucleus, and the outline of this is brought into 

 view, whereas if the carbonic acid is speedily replaced 

 by air, which may be effected by disconnecting the 

 tube t from the wash-bottle 6' and drawing air 

 through it by the mouth, the precipitate is redis- 

 solved, and the nucleus is again made to disappear. 



Fig. 13. 



Apparatus for passing carbonic acid gas over a preparation under the 

 microscope. 



ft, bottle containing marble and hydrochloric acid ; b', wash-bottle: t, India- 

 rubber tube conducting the gas to the stage, s. 



It is of advantage in performing this experiment 

 to add a trace of moisture to the blood before the 

 observation; this may be most conveniently done 

 by breathing two or three times on the preparation 

 before placing it over the ring of putty. 



Preparation 17. Influence of warmth on 

 white corpuscles of Amphibia. The action of 

 gentle warmth in accelerating the movements of the 

 5 



