tortion of corpuscles, does not interfere with staining, is easily operated 
and preserves blood perfectly, at least, for several months. 
The method consists of the following steps: 
1. Mix one volume of perfectly fresh blood with three volumes of a 
two per cent. solution of formalin. 
2. Allow the mixture to stand at least an hour; then draw a small 
quantity from the bottom of the vessel with a pipette, by which a drop 
is transferred to a clean coverslip; spread evenly over the coverslip and 
allow the liquid to evaporate. The method of pressing the coverslips to- 
gether, as in sputum analysis, is to be preferred. 
3. Pass the coverslips through the flame, films uppermost, in order to 
cement the corpuscles to the glass. 
4. Dip into a five per cent. solution of acetic acid once or twice. 
5. Remove the acid with water. 
6. Stain. Perhaps the best stain for non-nucleated corpuscles is Gen- 
tian violet (a two per cent. solution; time of staining, about two or three 
minutes). For nucleated forms, contrast stains, as Methyl blue and Gen- 
tian violet, or Hzematoxylin and Eosin, or Methyl green and Safraum, give 
very good results. Ehrlich’s Triple stain may be used for human cor- 
puscles, 
7. Wash out excess of stain with water or alcohol as the stain re- 
quires. 
8. Remove alcohol with clove oil or xylol, and 
9. Mount in Canada Balsam. 
This method proved very successful in the laboratory of Purdue Uni- 
versity, and was used in studying five different forms of corpuscles. They 
were those of the cat, the ox, the pigeon, the chicken, and man. The hu- 
man corpuscles were the only ones which resisted the stains, but this 
difficulty was overcome by the use of a weak solution of acetic acid. Be- 
sides making the stains effective, it also clears the films considerably. Al- 
though this method may be of no chemical value it promises to be success- 
ful for general laboratory purposes. 
