260 CLINICAL BACTERIOLOGY AND H^EMATOLOGY 



now almost obsolete, but occasionally useful when a study of 

 the granulations of the leucocytes is of importance. 



1. Ehrlich's stain consists of a mixture of acid fuchsin, 

 orange G, and methyl green dissolved in water, glycerin, and 

 alcohol. It is difficult to prepare, and should be purchased 

 from a trustworthy maker. Its use is very simple. The film 

 is fixed by heat in the manner already described, and the stain 

 is poured on to it, and allowed to act for five minutes. The 

 film is then washed, dried with blotting-paper, and then by 

 gentle heat, and mounted in balsam. 



Nuclei are stained green, red blood-corpuscles orange, and 

 eosinophile granulations bright red. The small eosinophile 

 granulations which are present in the polymorphonuclear 

 cells (the neutrophile granulations of Ehrlich) are stained a 

 purplish or coppery colour. The basophile granulations are 

 unstained. 



This stain is not suitable for the parasite of malaria, nor for 

 bacteria. 



2. Jennets stain consists of a solution of a compound of 

 eosin and methylene blue in methyl alcohol. It must be 

 bought ready prepared. Nothing could be more simple than 

 the way in which it is used; no preliminary fixation is neces- 

 sary, the film being allowed to dry and flooded with the stain. 

 After a period of from a minute and a half to three minutes, 

 the stain is washed off by waving the film to and fro in dis- 

 tilled or rain water for a few seconds, and the specimen dried 

 by blotting it between two pieces of clean blotting- or filter- 

 paper, allowed to get quite dry, and mounted in balsam or 

 cedar-oil, and the specimen dried and mounted.* 



After the use of this stain nuclei are stained blue, red cor- 

 puscles red, eosinophile granules red, and basophile granules 

 violet. The descriptions of the leucocytes and abnormal red 

 forms, which are appended, are all based on the appearances 

 seen in films stained by this method, from which also Plates 

 VII. and VIII. were drawn. 



* It has been objected that Jenner's method does not always give good 

 results, and that the above is an. insufficient account of the process. Provided 

 that the stain is good (Grubler's can always be relied on, and will keep for 

 several months after being opened, if kept well corked), the method described 

 ill always succeed if well-spread films are used. This is essential. But even 

 with bad films (and very bad ones are sent me at times) the results are always 

 sufficiently good to allow a differential leucocyte count to be made. 



