MERES 85 



can only be clearly understood through a knowledge 

 of these substances ; while the pharmacological 

 action of substances and the process of immunisation 

 will only become enlightened by a clear apprehension 

 of the mode of action of colloid upon colloid and the 

 interaction of crystalloid and colloid. The chem- 

 istry of the colloids is only in its infancy, but good 

 work has been done by Graham, Butschli, Pauli, 

 Fischer, Bernstein, Billitzer, and others, which has 

 done something to disperse the mists by which the 

 subject is obscured. 



Living cells consist of a complex mixture of col- 

 loids and crystalloids whose relations are ever varied ; 

 and the colloids are chiefly proteioidal and lipoidal 

 substances, and the changes in the structure of living 

 matter consist largely of changes in the colloids. 

 " Connected with the uninterrupted vital activity of 

 the cell, the anabolism and catabolism of its struc- 

 ture, is the conversion of crystalloids into colloids 

 and colloids into crystalloids,"* which is constantly 

 going on. The reaction of living matter may there- 

 fore be elucidated by a study of the changes in state 

 ex corpore of colloids and particularly of those called 

 proteins. 



Protoplasm possesses characteristics of both solid 

 and liquid substances. The ability to stand alone 

 agrees with the properties of solids, and this is seen 

 in the independence of cells. An argument for the 

 fluidity of protoplasm is however found in the con- 

 dition that chemical reactions take place in the cell 



* Fault's "Physical Chemistry in the Service of Medicine," 

 p. 43. 



