COUNTING GRANULES 281 



of the cells should be deeply stained. If the nuclei 

 are not yet stained, a little more alkali must be added 

 to the jelly and a fresh specimen made. If the cells 

 are achromatic or disorganised, or if the nuclei of the 

 neutrophile cells are deeply stained, the jelly is too 

 alkaline, and a little acid solution must be added to it. 

 But if the coefficient jelly and other solutions are 

 correct, the nuclei of the eosinophile cells will just be 

 staining. 



Using a |-inch or equivalent objective the specimen 

 is searched until a suitable eosinophile cell is found. 

 If a cell is distorted or hemmed in by red cells, it is 

 necessary to pass it over and find another. 



If there is any doubt as to whether a cell is an 

 eosinophile or basophile one, the slide is removed from 

 the mechanical stage in such a way that on returning it 

 to the microscope the same field can be focused again. 

 The slide is then again incubated for three minutes, but 

 at 47 C. On examination of the cell, if it is an eosino- 

 phile leucocyte, its granules will still appear scarlet ; but 

 if it is a basophile cell, its stained chromosome granules 

 will have turned black 1 (fig. 89). With a little experi- 

 ence of the method of staining, however, the difference 

 between the classes of cell can be detected without this 

 procedure of incubation at 47 C., which is apt to cause 

 premature rupture and achromasia. 



The next step is to burst the cell. The photo- 

 micrographic apparatus being ready on its slide above 

 the observer's head, the immersion objective is " turned 



1 These granules may turn black at 37 C. We have no explanation to 

 offer of this phenomenon. 



