124 PHYSICAL CHEMISTRY IN MEDICINE. 



may be brought about in a great variety of ways, also 

 seem clearer as soon as the exit of the coloring-matter 

 from the blood-corpuscles is looked upon as a rupture 

 of the colloidal haemoglobin- stroma compound. There 

 seem to exist, therefore, a large number of light-bringing 

 relations between immunity phenomena and phenomena 

 in colloid chemistry. LANDSTEINER in conjunction with 

 JAGIC have been able to show the identity existing between 

 the mechanism of the haemolysis (studied by KYES and 

 SACHS) brought about through the unknown cobra poison 

 and the mechanism of the haemolytic effect of colloidal 

 silicic acid. In this case a structurally uniform inorganic 

 colloid behaves like the haemolytic amboceptor of the 

 side chain theory. 



We are indebted to the same investigator for recog- 

 nizing a fact of still more general significance. The 

 protein's, and from many facts at our disposal the immune 

 bodies also, represent so-called amphoteric electrolytes; 

 in other words, substances which assume basic properties 

 in acid solutions and acid properties in alkaline solutions; 

 or, as shown by experiment, change the sign of their 

 electric charge with a change in reaction. There exists, 

 however, a zone between the extreme changes in the 

 sign of the electrical charge in which these hermaphrodite- 

 like substances respond to the slightest change in their 

 surroundings with an alteration in their electrical char- 

 acter, through which the existence of a large number of 

 finely graded relations between amphoteric electrolytes 

 differing only slightly from each other is rendered pos- 

 sible. This enormously changeable sensitiveness of such 

 substances, which may, according to circumstances, act 

 at one time as colloids having one kind of electrical 



