484 IMMUNITY. 



creases after the blood is shed and some time later gradually 

 diminishes. 



In addition to haemolytic sera, anti-sera have been obtained 

 by the injection of leucocytes, spermatozoa, ciliated epithelium, 

 liver cells, nervous tissue, etc. The laws governing the pro- 

 duction and properties of these are identical, that is, each serum 

 exhibits a specific property towards the body used in its produc- 

 tion i.e. dissolves leucocytes, immobilises spermatozoa, etc. 

 It may also be mentioned that each anti-serum usually exhibits 

 toxic properties towards the animal whose cells have been used 

 in the injections, e.g. a haemolytic serum may produce a fatal 

 result, with signs of extensive blood destruction, haemoglobinuria, 

 etc., i.e. it is haemotoxic for the particular animal ; a serum 

 prepared by injection of liver cells has been found to produce on 

 injection necrotic changes in the liver in the species of animal 

 whose liver cells were used. These are mentioned as examples 

 of a very large group of specific activities. 



With regard to the sites of origin of immune-bodies our 

 information is still very deficient, Pfeiffer and Marx brought 

 forward evidence in the case of typhoid, and Wassermann in the 

 case of cholera, that the immune-bodies are chiefly formed 

 in the spleen, lymphatic glands, and bone-marrow. According 

 to certain workers of the French school, the chief source of 

 sera acting on cells such as red blood corpuscles is the large 

 mononucleated leucocytes, whilst sera acting on bacteria are 

 chiefly derived from the polymorpho-nuclear leucocytes. The 

 active bodies in the former are by these observers sometimes 

 spoken of as " macrocytases" those of the latter as " microcy- 

 tases" Another view is that immune-bodies are chiefly formed 

 by the large mononucleated leucocytes, whilst complements are 

 products of the polymorpho-nuclears. That these cells are con- 

 cerned in the production of antagonistic and protective sub- 

 stances is almost certain, though another possible source of wide 

 extent, viz., the endothelium of the vascular system, has been 

 largely overlooked. As yet, definite statements cannot be made 

 on this point. 



Agglutination. Charrin and Roger in 1889 observed that 

 when the bacillus pyocyaneus was grown in the serum of an 

 animal immunised against this organism, the growth formed a 

 deposit at the foot of the vessel ; whereas a growth in normal 



