1906.] 



The Viscosity of the Blood. 



347 



the size of the capillary bore of the viscosimeter, and with different bloods on 

 the relative sizes of the corpuscular elements. Naturally we cannot expect 

 the addition of the corpuscles per se as semi-solids, and their variations 

 in size, to have any appreciable effect on the viscosity unless they are to pass 

 through capillary tubes of radius comparable with their own dimensions. 

 Against Hiirthle's statement, already mentioned, that " almost identically the 

 same values were found for the viscosity of the blood of one and the same 

 individual animal when tubes of various sizes and varying arterial pressures 

 were employed," it is to be urged that his method of attacking the question 

 did not admit of his obtaining a sufficient experimenbal range from which 

 reliable conclusions could be drawn. From the experimental results recorded 

 in Table V, for which a large quantity of blood was available, whilst 

 viscosimeter tubes of bores varying from 2 mm. to - 3 mm. could be directly 

 employed, and " artificial " blood mixtures with widely differing numbers of 

 corpuscles easily made up, it will be seen that the smaller influences of each 

 successive alterations become, as it were, of magnified importance, when 

 viewed as parts of a bigger scheme, and show at once that blood containing 

 a large number of corpuscles encounters considerably greater resistance to its 

 flow than is to be expected from an application of Poiseuille's law, in its 



Table V. — Showing the Variation of the Viscosity Values with the size of 



the Capillary Bore. 



Capillary bore. 



2 mm. 



1 mm. 



1*6 mm. 



-3 mm. 



Temperature. 



V- 



R. 



V- 



E. 



V- 



R. 



V- 



R. 





Plasma from 1 per cent, potassium oxalate. 







32°2 

 40-4 





-0130 

 -0110 



1 -8 

 1 5 



-0139 

 -0119 



1-9 

 1-6 



-0140 

 -0121 



1-9 

 1 -6 



-0141 

 -0121 



1 -9 

 1 -6 





Plasma + 3'6 



x 10 6 corpuscle 



s per cubic millimetre. 







32 -2 

 40-4 





-0202 

 -0180 



2-7 

 2-4 



-0241 

 -0221 



3-3 

 3-0 



-0272 

 -0244 



3-7 

 3-3 



-0338 

 -0304 



4 -6 

 4-1 





Plasma + 6-0 



x 10 6 corpuscle 



3 per cubic millimetre. 







32 -0 

 40-4 





-0265 



3-6 



-0333 

 -0302 



4-5 

 4-1 



-0402 

 -0368 



5-5 

 5-0 



-0546 



7-4 





Plasma + 9 - 6 



x 10 6 corpuscles per cubic millimetre. 







32-0 

 40-4 





0-0474 

 0-0428 



6-5 

 5-8 



-0562 

 -0513 



7-5 

 7-0 







-0982 



13-4 



