( 159 ) 



greater, and by the addition of 0.5 % Ca Cl s 6 aq., it again 

 decreases. 



The result registered in the first instance, which is produced by 

 the addition of 0.01 % CaCl,, must be considered the most valuable, 

 for it denotes the nearest unalloyed effect of the calcium chloride. 

 In the experiments where quantities of O.J %> 0.5% and J % of Ca CI, 

 were added, the increase of phagocytosis is counteracted by the 

 unfavourable influence of the raising of osmotic pressure. 



This experience is in strict accordance with the observations made 

 by Langendorff, who found that the injection of very small quantities 

 of calcium, causes the heart to beat with greater force. We ascribe 

 this manifestation to the action of the ion of calcium on the contractile 

 substance, and we may conclude that the muscular fibre and the 

 phagocytes also, are permeable to this cation. 



4. Effect of citras natricus. 



The frequent use which, in consequence of the experiments of 

 Wright and Douglas, ') is made of this medium at the present day 

 by the bacteriologists, in order to prevent the coagulation of the blood, 

 actuated us also to experiment with this substance for the sake of 

 determining its action on the phagocytosis. The following table gives 

 a survey of the results. 



The customary solutions of 1 % am ' 2 % of citras natricus in 

 0.9 7o solution of sod. chl. were used in these experiments. 

 TABLE X. 

 Effect of citras natricus. 



l ) Wright and Douglas, Proceed, of the Roy. Soc. 72, 1903, p. 357; 73, 1904, 

 p. 128. 



Jl 

 Proceedings Royal Acad. Amsterdam. Vol. X. 



