Action of Sodium Glycocholate. 



101 



The Action of Histidine. 



Histidine acts in a manner similar to histamine in accelerating haemolysis 

 by sodium glycocholate, and, if used in another way, in protecting cells 

 against haemolysis by histidine and glycocholate. In general, its action in 

 these respects is less marked than that of histamine. 



These properties belonging to histamine and to histidine do not appear to 

 be general properties of amino-acids. Glycine and arginin, for instance, do 

 not possess them. A full study of this question is being made, and the point 

 will not be further dealt with in this paper. 



Discussion. 



It is a much easier matter to observe the phenomena described in this 

 paper than to explain them. A brief discussion of certain points is 

 desirable. 



It appears obvious that the explanation of haemolysis by sodium glyco- 

 cholate on the grounds that this salt dissolves the envelope of the corpuscle 

 is inadequate, in view of the unusual behaviour of the salt in certain high 

 concentrations, and especially in view of the action of non-hfemolytic 

 substances like histamine when in the presence of a blood suspension and 

 sodium glycocholate. A more probable explanation is one which is based on 

 changes of surface tension ; possibly the solvent action of the salt plays a 

 subsequent part. To advance a theory to explain these occurrences is at 

 present impossible ; the following suggestion, however, is supported by the 

 majority of the facts, and may be taken as a working hypothesis, useful for 

 the present until further facts are brought to light. 



If we consider first the addition of blood cells to a solution of sodium 

 glycocholate, we may say that two occurrences take place : (1) the glyco- 

 cholate becomes condensed at the interfaces, and therefore on the surface of 

 the red cells ; and (2) a solvent action of the glycocholate on the envelope of 

 the cell begins. If histamine, which it has been seen, powerfully disturbs 

 colloid solutions, be added, the colloidal glycocholate probably undergoes a 

 sudden change of physical state, resulting in a sudden variation of the surface 

 tension at the red-cell interfaces, where the glycocholate is collected. This 

 sudden alteration ruptures the cell wall, all the more so as the glycocholate is 

 already attacking the envelope, and therefore is; as it were, continuous with 

 the substances composing it. The rapid haemolysis produced by the addition 

 of histamine may be thus explained. If, on the other hand, the histamine be 

 added to the cells first, it will not be so condensed at the interfaces as the 

 colloid would be, and will certainly not dissolve the envelope. On the 



VOL. xcili. — B. I 



