214 CHEMISTRY OF THE IMMUNITY REACTIONS 



the terpenes, shows that their hemolytic activity varies much accord- 

 ing to their physical properties, generally decreasing directly with in- 

 crease in the solubilitj' in water (Ishizaka).-*^ 



Leucocytes are dissolved by some of these agents, particularly the bile salts 

 although they are affected by no means so rapidh^ or so much as are the erythro- 

 cytes. There seems to be no relation between the erythroh^tic and leucolytic 

 powers of these substances. Water causes swelling, with solution of the granules 

 in time, and the same is true of ammonium-chloride solutions. 



Various chemicals cause morphological alterations in the leucocytes, and of 

 bacterial products the toxins of pyocyaneus and diphtheria seem to be particularly 

 leucocidal, causing a striking karj'orrhexis (Schiirmann)." 



Hemolysis by Serum 



Normal blood-serum of many animals causes hemolysis to greater 

 or less degree when mixed with red corpuscles of another species of 

 animal, and this property can be greatly increased by immunizing 

 the animal with red corpuscles in the usual way. This hemolysis oc- 

 curs both in the test-tube and in the body, in the latter case causing 

 severe anatomical changes or even death. In all respects the mech- 

 anism of hemolysis by serum seems to he identical with that of bac- 

 teriolysis. Two substances are concerned, one the amboceptor, which 

 resists heat and which is increased by immunizing;*^ the other, com- 

 plement, which is destroyed at 55° and which is present in normal 

 serum. In this case the substances may be referred to as hemolytic 

 amboceptors and hemolytic complements. 



In spite of the availability of these particular cytolytic substances 

 for study, very little has been learned of their exact nature and prop- 

 erties. It is known that amboceptor is combined with the red 

 cells in a certain sense quantitatively, a definite amount being re- 

 quired to saturate a given amount of corpuscles so that they will all 

 be hemolyzed when complement is added; and that this reaction is 

 complete in less than fifteen minutes at 45°. What change this addi- 

 tion of amboceptor brings about in the corpuscles is unknown. It 

 has also been shown that at 0° the affinity between the amboceptor 

 and the corpuscle is greater than it is between amboceptor and com- 

 plement, so that it is possible at this temperature to remove all the 

 amboceptor from a serum by treating it with red corpuscles, and 

 thus we can obtain complement free from amboceptor. This experi- 

 ment also shows that the two bodies exist side by side in the serum 

 without combining, and that combination occurs only after the ambo- 

 ceptor has become united to the erythrocyte. Moreover the hemoly- 

 tic amboceptor can be separated from the antigen to which it has been 



" Arch. exp. Path., 1914 (75), 195. 



** Cent. f. Pathol., 1910 (21), 337. 



*^ In an extensive study of the hemolytic antiI)ody, Thiele and Embleton 

 (Zeit. Imnuinitiit., 1913 (20), 1) describe its formation as in several steps, at first 

 being tlicrmolabile and uniting with the corpuscle only when warmed. They 

 also find complt^ment to have sev(>ral components. This is not coufiriued by Siier- 

 man, Jour. Infect. Dis., 1918 (22), 534. 



