1894.] MICHOSCOPICAL JOURNAL. 265 



Microscopical Technique Applied to Histology.— VI. 



[FROM THE FRENCH OF REKE BONEVAL.] 



Conthiued from page 24S. 



Permanent PreparaUo7is of Blood. — . . . .Spread a blood 

 drop as tliin as possible on a slide. Pass to and fro over 

 an alcohol flame until dry. The corpuscles are thus 

 fastened to the glass in their natural form and size. . . . 



Frog's blood fixed by heat may be stained by eosine 

 and by methyl green. Stain for 3 minutes with a few 

 drops of the following : eosine, 2 ; water, 50 ; alcohol, 

 50. Dissolve the eosine in the alcohol and add the wa- 

 ter. Wash gently, and stain for 2 minutes with an aque- 

 ous solution of methyl green. Wash, dry and mount in 

 balsam, after clearing by oil of bergamot. The globules 

 are red, the nuclei and leucocytes green. . . . 



To preserve the red corpuscles in a tissue to be sec- 

 tioned use, as a fixative, picric acid or 2 per cent am- 

 monia bichromate. Complete the hardening by alcohol, 

 imbed in gum ; the corpuscles will not be changed as 

 they would be if the tissue was fixed by alcohol alone. 

 Stain the sections by hajmatoxyliu and eosine ; mount in 

 balsam. . . . 



FIBRIN. 



... .A capillary tube with excedingly thin walls, filled 

 by being thrust directly into a frog's artery, is placed on 

 the microscope stage and examined with a high power. 

 " At first the red globules fill the tube. In a few min- 

 utes coagulation takes place, and the cylindrical mass 

 imprisoning the globules is seen to be separated from 

 the glass by a transparent space which contains not a 

 single corpuscle. Then the white corpuscles begin to 

 leave the coagulum and to float in the serum. Seeing 

 the activity of these amoeboid movements, one would be 

 tempted to attribute them to the escape of these anatom- 

 ical elements from the clot, but this is an illusion as will 



