140 BACTERIOLOGY FOR NURSES 



antigen. Complement is a delicate substance, destroyed by a 

 moderate temperature (55 C.), and disappears from serum that 

 is kept for a few days. Like the ferments it is somewhat unstable, 

 but it differs from them in being " fixed " or used up in definite 

 quantities. 



Bacteriolysins are produced only in the case of certain organ- 

 isms, and of these the typhoid and cholera groups are the most 

 notable. 



Lysins may be produced by antigens other than bacteria. If 

 an animal be injected with the body cells of another species it 

 develops antibodies, cytolysins, which when combined with comple- 

 ment disintegrate the same type of cells that were employed for 

 their production. Cytolysins have been obtained with leukocytes, 

 kidney cells, and other organs and tissues. When the cytolysins 

 were first discovered they aroused great enthusiasm in the hope 

 that it might be possible to disintegrate and dissolve such foreign 

 cells as cancer and other tumors. Unfortunately, the results 

 have been disappointing ; the cytolysins are comparatively weak 

 and not very specific. 



Hemolysins have perhaps been the most studied of all the 

 lysins, owing to the ease with which the reaction may be observed. 

 It has long been known that in some instances the blood serum 

 of one animal has the power in a certain degree of dissolving the 

 red blood cells of an animal of a different species. Bordet demon- 

 strated that if an animal were given repeated injections of the red 

 blood corpuscles of another species the serum of the former acquired 

 the property of dissolving the red blood cells of the latter. He 

 found also that this property disappeared when such serum was 

 heated at 55 C., but as in the case of other lytic serum it 

 was regained when fresh serum from a normal animal was 

 added. It was evident that the immune serum contained a new 

 substance, the amboceptor, which in the first instance had united 

 the cells with complement and brought about their destruc- 

 tion, and in the second case it was amply demonstrated that 

 not only is complement destroyed by a lower temperature than 

 amboceptor, and that it is indispensable for the reaction, but also 



