CHAP. IV.] THE BLOOD. METHODS OF EESEARCH. 



175 



which was weighed. Let us assume that we have found our bottle to hold 

 25-6515 grams of water at 15, and 2 7 '2 70 grams of defibrinated blood at 

 7 C. ; we must first calculate the weight of water which would be con- 



FIG. 28. SPECIFIC GRAVITY BOTTLE, 

 consisting of a light flask with a well- 

 ground perforated stopper. 



FIG. 29. 



GEISSLER'S SPECIFIC GRAVITY 

 BOTTLE. 



a ig & ^ flagt & a yery accurately 



graduated thermometer, c is a tube con- 

 nected with a, through which fluid escapes 

 when the thermometer is inserted in the 

 bottle, d a cap which fits perfectly the 

 top of c and which is applied to it after it 

 is filled. 



tained if the temperature had been 7 and not 15. We find on looking at 

 the subjoined table of the specific gravities of water that whilst the specific 

 gravity of water at 15 is 0'99915, at 7 it is 0*99994, and we can get the 

 weight of water which our bottle would hold at 7 by the following 

 proportion : 



0-99915 : 0-99994 :: 25-6515 : x 

 _ 0-99994x25-6515 _ 



0-99915 -^o'- 



