1893.] and other Varieties of Liquid Extravascular Blood. 565 



results of these enumerations here, and to direct attention to the 

 bearing of the results obtained in the case of peptone blood. 



I may premise with respect to the methods employed that the 

 enumerations were made by diluting the blood 200 times with an 

 8 per cent, solution of magnesium sulphate, which had received a 

 sufficient addition of gentian-violet to stain the cells darkly in the 

 course of a few minutes. The enumerations were invariably made 

 in duplicate samples of each blood, and in each sample the absolute 

 number of leucocytes was counted on 250 squares of the Gowers 

 haBmocjtonieter. An agreement within 10 per cent, was exacted 

 between the counts of the duplicate samples. When this was obtained 

 the counts were added together, and their sum multiplied by 200 to 

 obtain the total number of leucocytes in th3 cubic millimetre. The 

 following are the results of my enumerations in oxalated, leech- 

 extract, and peptone blood. 



Oxalated Blood. 



Obtained by drawing off 9 vols. of blood into 1 vol. of a 1 per cent, 

 oxalate of soda solution. 



Leech-extract Blood. 



Obtained by extracting 3 vols. of blood from carotid into "2 vols. of 

 leech-extract. The leech-extract was made from leeches which had 

 been kept under alcohol for several weeks. 



