THE BLOOD. 



245 



bit, sheep; (3) easy cat, dog, mouse, horse; (4) very easy guinea- 

 pig, rat. 



The hemoglobin crystals vary in shape according to the blood 

 from which they are obtained (Fig. 101). Those obtained from the 

 guinea-pig are tetrahedral; those 



from man and 

 are jprismatic 



most mammals 

 .rhombs; those 



from the squirrel are in the form 

 ,of hexagonal plates. Notwith- 

 standing these slight differences, 

 all forms belong to the same 

 crystal system, with the excep- 

 tion of those from the squirrel. 



A simple but very effective 

 method of obtaining blood-crys- 

 tals suggested by Reichert is to 

 lake defibrinated blood, espe- 

 cially that of the dog, rat, guinea- 

 pig, and horse, with acetic or 

 ethylic ether and then add a 

 solution, i to 5 per cent., of 

 ammonium oxalate. A drop of 

 this mixture placed under the 

 microscope will show crystal for- 

 mation in a very few minutes. 



Chemic Composition of 

 Hemoglobin. By appropriate 

 methods hemoglobin can be ob- 

 tained in a practically pure form, 

 and when subjected to a tem- 

 perature of 100 C. its water of 

 crystallization is driven off, after 

 which it can be analyzed. In 



the subjoined table the results of several analyses are given for 100 

 parts of hemoglobin. 



FIG. 101. CRYSTALLIZED HEMOGLOBIN. 

 a, b. Crystals "from venous blood of 

 man. c. From blood of cat. d. Of 

 Guinea-pig, e. Of marmot. /. Of 

 squirrel. (Gautier) . 



