1907.] Fatty Degeneration of the Blood. 439 



may be excluded. In medullated nerve fixed in formol and afterwards 

 teased and immersed in Scharlach solution for 24 hours, the myelin of the 

 individual fibres exhibits practically no coloration; it is equally unaffected 

 bv osmic acid, if the nerve is first fixed in formol. 



As regards the coloration of human fats, that is, of their fatty acids which 

 are the proper colourable substances, pure oleic acid is stained of the typical 

 red colour with 75-per-cent. alcoholic solution of Scharlach. 



From human liver Leathes has extracted another fatty acid, the colour- 

 ability of which we have been able to test upon cover-glass smears. The 

 smear, after being treated with formol vapour, stained with Scharlach, and 

 finally washed in distilled water and mounted in Farrant's medium, is trans- 

 parent, and of an orange or orange-brown colour ; it presents nothing 

 suggestive of the Scharlach granulation. 



From human heart-muscle Leathes has also extracted a fatty acid other 

 than oleic, and not identical with that referred to from the liver. 



The fact, however, that in fatty degeneration of this muscle, as studied in 

 diphtheria, the fat that appears is from the first stained of a brilliant red by 

 Scharlach shows that, whatever fat besides olein may be present, it is not the 

 substance constituting the Scharlach granulation. 



There is, to conclude, the possibility that the granulation is due to a soap, 

 the colloidal nature of which prevents its diffusion into the substance of the 

 cell. 



Various fermentative capabilities have been ascribed to the leucocytes. 

 They are certainly proteolytic ; and both amylolytic and lipolytic powers have 

 been attributed to them. 



It is conceivable that the fat droplets, on their first appearance in the 

 leucocytes, might be split, with the resulting formation of an intracellular 

 soap arising from the combination of fatty acid with calcium, sodium, or 

 potassium. 



Using pure oleate of calcium (the only soap of the three not soluble in 

 water), we find that cover-glass smears, after being treated as the blood 

 films, fail to exhibit the dark brown colour and opacity of the Scharlach 

 granulation ; the particles take a pale brown or orange tint. 



For the present, therefore, we are forced to leave the nature of the 

 Scharlach granulation undetermined. Nevertheless, its appearance in 

 diseases in which a fatty degeneration of the leucocytes might have been 

 anticipated, and the fact that in some cases of acute pneumonia the 

 proper Scharlach reaction of the points in the cells is obtained, whilst in 

 others it is the brown opaque Scharlach granulation, makes us conclude that 

 the granulation is indicative of a degeneration : and seeing that it is not 



