90 NORMAL HISTOLOGY. 



the swelling of all the red blood-cells, and second, in dis- 

 solving the haemoglobin out of them. 



Crystals of Hczmoglobin from Rat's Blood. Although 

 readily separated by water from its combination with the 

 stroma of the red blood-cells of man, the haemoglobin 

 does not readily crystallize. But when separated from 

 the red cells of certain animals, the rat for example, it 

 commences to crystallize, under favorable conditions, 

 almost immediately. A small drop of rat's blood is mixed 

 on a slide with an equal quantity of water, covered and 

 examined at once. The color begins to be discharged 

 from the red cells very soon, and within a few moments, 

 near the edges of the cover-glass, small crystals may be 

 found in abundance. If the specimen is set aside and 

 examined after a few hours, many very large and beauti- 

 ful prismatic crystals may be seen. Haemoglobin crystals 

 do not keep long enough for permanent preservation. 



Demonstration of the Nuclei of the White Blood-cells. 

 In order to see their outlines distinctly, the nuclei must 

 be stained and the cell-body rendered transparent. This 

 may be accomplished by mixing on a slide a small drop 

 of blood from the finger with an equal quantity of the 

 following fluid : 



Saturated alcoholic solution of Fuchsin . l part, 



Alcohol 5 parts, 



Water . ^ 10 parts. 



After thoroughly mixing the blood with the fluid, and 

 covering, it will be found that while the red cells are 

 partially decolorized and inconspicuous, the bodies of 

 the white blood-cells have become transparent and their 

 nuclei are stained deep. 



