1906.] 



The Viscosity of the Blood. 



345 



these salts decreased the viscosity, yet the extent of the reduction is 

 apparently quite a variable quantity ; indeed it depends to a large extent upon 

 the internal composition of the particular blood examined, and on the initial 

 action of its constituents and the added salts. 



Ewart has also observed that additions of dilute saline lowered the viscosity, 

 whereas an increase of acidity or alkalinity, as well as the addition of many 

 neutral salts, caused an increase in viscosity. The fall in viscosity he attributes 

 to a reduction of the quantity of albumin, etc., and the fall of proteid strength. 



When considering the effects of changing the concentrations of the salt 

 solutions, etc., present, it should be borne in mind that whenever an animal 

 cell is brought into a strong salt solution, the osmotic pressure of which 

 is greater than that of the cell sap, the cell contracts and becomes flaccid, 

 owing to the passage outwards of certain constituents of the sap, whilst the 

 effect of placing the cell into a dilute solution, the osmotic pressure of which 

 is less than that of the cell sap, will cause the cell to expand and even 

 eventually burst. As hsematocrite and other experiments have shown, the 

 blood corpuscles are affected in the same way ; in strong solutions they are 

 crenated ; in dilute solutions they may burst and allow the red colouring- 

 matter to pass into the surrounding liquid. Duncan and G-amgee have shown 

 that laking causes a diminution of viscosity. 



But the study of the effect of changing the concentration of the chemical 

 bodies present in the blood is still further complicated by the fact that the proto- 

 plasmic cell walls may vary considerably in their permeability. For instance, 

 Dr. Loeb, of Chicago, asserts that the eggs of sea urchins, if placed in con- 

 centrated solutions of NaCl, die at once, but show increased vitality if a tiny 

 quantity of certain metallic salts be present. Experimenters with colloidal 

 liquids have frequently noticed how the addition of certain reagents may some- 

 times bring about changes in some particular property of the colloid, which are 

 altogether out of proportion to the weight or bulk of the added reagent, e.g., 

 one drop of a weak FeCl 3 solution to about 50 c.c. of colloidal Fe (OH) 3 has 

 been observed to lower the viscosity of the latter by 500 per cent.* Whilst 

 Majoranaf and Schmausj have found that the smallest traces of the chloride 

 were sufficient to destroy all traces of the magnetic double refraction of the 

 colloidal iron hydrates, etc. 



The study of the influence of various salts upon the viscosity of the blood 

 is obviously a province in which much work has yet to be done in order to 



* Vide Denning, 'Ueber die Viscositat, etc., des colloidalen Eisenoxydhydrates, 

 Inaugural-Dissertation, Heidelberg, 1904. 



t Qu. Majorana, ' Eendic. Acc. del Lincei,' II, vol. 1, p. 374, etc., 1902. 

 % Schmaus, 'Ann. der Physik,' vol. 10, p. 658, vol. 12, p. 186, 1903. 



