H^MOLYSINS AND AGGLUTININS OF PLANTS 463 



have been unable to obtain proteid-free ricin ; the active product 

 which they obtained by very careful work gave an elementary 

 composition identical with proteid; it also gave certain of the 

 proteid reactions. 



It is of interest to note in this connection that other vegetable 

 poisons, such as alkaloids, do not produce anti-bodies. In fact, 

 we do not know of any substance, whose chemical structure is 

 accurately known, which does. The discovery of the chemical 

 constitution of any of these poisons which can, when inoculated, 

 lead to the production of anti-bodies would be of inestimable 

 value, for then a much clearer insight could be obtained into 

 the chemical nature of anti-bodies and of their numerous modifi- 

 cations. 



Abrin, a phytalbumose obtained from the seeds of Abrus pre- 

 catorius, also possesses toxic and agglutinating properties, and, 

 by inoculation, anti-bodies can be produced against its action. 



The agglutinating properties of these two vegetable toxins are 

 very closely related to a hsemolysing action shown by certain 

 other phytalbumoses such as phallin and crotin. The latter 

 poison produces haemolysis of rabbit's erythrocytes and agglutina- 

 tion of those of the sheep, pig, and ox. There can, therefore, be 

 no doubt that the two processes are akin, and Ehrlich suggests 

 that the agglutinating substance of phytalbumoses, which is the 

 most evident, is the same thing as the haemolysing substance ; the 

 agglutination, where it alone is exhibited, hindering haemolysis 

 by clumping the corpuscles together. In fact, Baumgarten has 

 shown that vigorous shaking of erythrocytes agglutinated by 

 means of ricin and abrin causes partial haemolysis. It is difficult 

 to see, however, how this view of Ehrlich can be accepted, if he 

 considers as different, the agglutinins and haemolysins derived 

 from other sources. 



CYTOTOXINS 



Erythrocytes and bacteria are not the only animal cells which 

 can, when injected into an animal, cause lysogenic substance to 

 be formed. Any other animal cell can do the same thing. Thus, 

 as was discovered by Metchnikoff ( 13 ), if the leucocytes of a rabbit 

 (lymphatic gland or red marrow of bone) be injected every four 

 days into a guinea-pig for several weeks, the serum of the guinea- 

 pig will, if added to rabbit's leucocytes, quickly dissolve them. 

 This can be observed under the microscope. The so-called 



