240 SCIENCE PROGRESS. 



function of some of these organs. After extirpation of the 

 spleen the latter observers (28) have found that rabbits 

 cannot be rendered refractary to tetanus by the introduction 

 of the serum of an immune animal. The part played by the 

 spleen might therefore be due to the fact that this organ either 

 produced a protective substance from the injected serum, or 

 rendered the toxic bacterial products innocuous. A con- 

 tinuation of this research (29) however seems to show that 

 the spleen plays no direct part in the production of immunity, 

 and that if there is a specific protective substance it is not 

 existent in this organ. Experiments have also shown that 

 removal of this organ either before or after protective inocu- 

 lation has no influence whatever on the acquired immunity 

 of rabbits against the bacillus pyocyaneus (30). The most 

 recent work bearing upon this question is that of Benario 

 (31). This observer removed the spleens of rabbits and 

 mice and then succeeded in rendering these animals immune 

 to tetanus or to a lethal dose of ricin or to infective bacilli. 

 Since extirpation of this organ has no influence whatever on 

 the production of acquired immunity against an intoxication, 

 a vegetable toxalbumin or an acute infective disease, the 

 view that the refractary state is connected with the function 

 of this gland can no longer be sustained. 



The thyroid, thymus and lymph glands have also 

 been regarded as an apparatus (33) where the various 

 intermediate products which are assumed to be formed by 

 the normal destruction of proteids within the circulation are 

 rendered harmless. This view corresponds to some extent 

 with the antitoxic function, which was at one time ascribed 

 to the liver by Schiff. To test the part played by these 

 organs experiments have been made upon extract of thymus 

 gland (33), an organ which may be regarded as a mass of 

 phagocytes. The bacilli of tetanus, cholera, diphtheria, ty- 

 phus, erysipelas, anthrax and hog-erysipelas were grown either 

 upon sterile aqueous thymus extract or upon thymus bouil- 

 lon. The material of the thymus cells has been found to 

 act in the reduction of the toxic properties of cultures of 

 these bacilli, and further, by the action of thymus material 

 on bacterial cultures products were obtained, which with 



