The Hcemolytic Action of Sodium Glycooholate. 87 



opalescence is not so rapid. If in a 1 per cent, solution in saline, the 

 opalescence takes days to appear. 



Both salts possess a property peculiar to colloids — they protect a gold sol 

 against precipitation by electrolytes. This protective power is shown in the 

 following way. Using a gold sol prepared by the formaldehyde method, 1 c.c. 

 is precipitated by O'l c.c. of 10 per cent. NaCl within 10 seconds. If small 

 quantities of bile salts be added, we find that precipitation is prevented. This 

 protective power is apparent before the solution becomes opalescent, and 

 becomes less as opalescence proceeds, attaining a minimum after about 

 36 hours. The smallest quantity of taurocholate and glycocholate respec- 

 tively which will protect 1 c.c. of gold sol against O'l c.c. 10 per cent. NaCl is 

 shown in the following Tables, the solutions being kept at 18° C. : — 



Table I. 



Hours after 

 preparation. 



Smallest protecting quantity. 



Taurocholate 

 (1 in 1000). 



Glycocholate 

 (1 in 1000). 





c.c. 



c.c. 



1 hour 



-2 



0-35 



12 hours 



0-3 



0-4 



24 „ 



0-35 



'55 



36 „ 



-4 



0-6 



48 „ 



0-4 



-6 



It will be observed that (1) the taurocholate is about twice as protective as 

 the glycocholate, and (2) that, as opalescence becomes established, there is a 

 loss of protective power, the minimum being about half the protective power 

 of the fresh solution. 



A more complete study of the physical chemistry relating to this subject is 

 being made. 



The Hcemolytic Action of Sodium Glycocholate. 



In a paper previously published (1), it has been pointed out that sodium 

 glycocholate behaves in a manner similar to that found in the cases of sodium 

 taurocholate, saponin, and other hemolytic agents. In dilutions higher than 

 1 in 1000, the rapidity with which this salt produces haemolysis depends on 

 the dilution, there being a relatively simple relation between the two. When 

 one examines the action of the salt in concentrations of 1 in 100, 1 in 500, 

 etc., a different behaviour is observed : in three respects especially. 



(1) There is great difficulty in obtaining consistent results ; this difficulty 

 does not ordinarily exist, for the time required for hemolysis can, as a rule, 



H 2 



