and Laboratory Methods. 2091 



MICROSCOPICAL EXAMINATION OF BLOOD. 



For making micro-preparations of blood, clean covers and slips are necessary 

 for the best results. Wash the covers in soap and water, alcohol, and a mixture 

 of alcohol and ether. Clean the point selected for the lancet with soap and 

 water, alcohol and ether. It must be perfectly dry. Wipe away the first drop 

 of blood, and touch the end of a clean slip to the next drop and rapidly apply it 

 to a cover held in a Cornet forceps, drawing the slip over the cover so as to 

 make a thin spread on the cover. This should be done rapidly, i. e., within two 

 or three seconds. The cover must not be touched with the finger, as the moisture 

 would crenate the cells. Dry in the air rapidly and drop it into equal parts of 95 

 per cent, alcohol and ether for two hours, after which it may be stained. 



The heat method of fixation gives better results except in some few cases 

 when special stains are to be used. In all ordinary cases it should be used. 

 Spread the blood on a clean cover-glass as directed above, and when dry put on 

 a blood table (Huber's) which should be heated at one end by an alcohol lamp 

 or Bunsen burner. Test the heat of the table by a small drop of water. Put 

 the covers, blood side down, on the table at the point just where the drop of 

 water boils and turns into steam. Fix for fifteen to thirty minutes. Stain with 

 any of the following stains : 



Ehrlich's Triacid Stain. — This stain is so difficult to make that it should 

 be purchased of some reliable dealer. Orange G., acid fuchsin, and methyl 

 violet are the dyes which compose it. Apply all of the stain that will remain 

 on the cover, which should be held in a Cornet forceps. Stain for fifteen 

 minutes, wash in water, dry between pieces of filter paper, and mount, blood 

 side down, on a clean slip, in a drop of balsam. The nuclei of the leucocytes 

 will be stained greenish ; the eosinophile granules, copper color ; neutrophile 

 granules, violet. The neuclei of basophile leucocytes will be pale green, while 

 the protoplasm will be unstained. Red corpuscles will be stained orange. If 

 they take a reddish tint it will be due to anaemic degeneration. 



HEMATOXYLIN AND EosiN Stain. — Stain two minutes in 1 per cent, yel- 

 lowish eosin in 70 per cent, alcohol, wash thoroughly and apply Delafield's 

 haematoxylin for three minutes, wash again thoroughly, dry, and mount in bal- 

 sam. The red cells will be stained red, the nuclei of white corpuscles will be blue. 



Jenner's Stain is a very useful one. It is prepared as follows : 

 ( Yellowish Eosin, - - - 1.2 grams. 



Sol. I ■} Distilled water, - - - 98.8 grams. 



(Mix. 



( Methylene Blue, - . . 1 gram. 



Sol. II } Distilled Water, - - - 99 grams. 



(Mix. 



These solutions should be thoroughly mixed in an open vessel and set aside 

 for twenty-four hours. Filter and dry the sediment. Powder this, wash it with 

 water, and again filter and dry. The powder so obtained should be used in ^ 

 of 1 per cent, solution in pure methyl alcohol. Add 10 per cent, glycerine, and 

 it is ready for use. The stain is applied to the blood preparation, which 

 requires no fixation. Stain for from one to three minutes, wash in water till the 

 film is pinkish in color, dry and mount in balsam. Red cells are stained terra 

 cotta color, leucocytes blue, neutrophile granules bright red, and basophile 

 granules violet. Malarial organisms and bacteria are stained blue. 



The stain is a very important one, easy to use and rapid, as no fixation of 

 the blood is required. For success the covers must be thoroughly clean. Wash 

 them in soap and water, ammonia and water, ether, and lastly absolute alcohol. 

 Dry without touching the surface with the fingers. William H. Knap. 



Harvey Medical College. 



