188 TOXINES AND ANTITOXINES. 



term " toxine," in the precise connotation that we have described, 

 which covers all the properties of this characteristic class of 

 bodies. 



Properties of Ricine. Ricine, like the bacterial poisons, 

 presents many close analogies with the enzymes, so much so that 

 it was classified with them by STILLMARK, although it does not 

 bring about any true fermentative processes, such as diastatic 

 action, <fec. Among these analogies is its property, mentioned 

 above, of being carried down by all kinds of precipitates ; 

 and this mechanical precipitation takes place with special 

 readiness in the case of subsiding proteid precipitates. Its 

 precipitation by nucleic acid must also be attributed to a 

 mechanical process of carrying down, and not to a characteristic 

 reaction of the toxine itself, such as TICHOMIROFF x claimed 

 to have observed both in ricine and in other toxines. It 

 also resembles the enzymes in its sensitiveness to physical 

 and chemical influences. 



The temperature of boiling water is extremely injurious to it, 

 although, according to JACOBY, it does not entirely destroy its 

 toxic property, and the purified poison offers greater resistance 

 than that containing proteid impurities. JACOBY considers it 

 not impossible that, on boiling, a different poison is produced, 

 possibly a toxoid. The toxine is not destroyed by dry heat, 

 110 C. (STILLMARK), and is almost unaffected by pepsin- 

 hydrochloric acid (MULLER). 



We have already described its behaviour towards trypsin, and 

 it is particularly interesting to note that JACOBY found that his 

 pure ricine was rapidly destroyed by trypsin, but that this did 

 not take place when fresh quantities of trypsin were added to 

 digested mixtures containing the unpurified ricine. Hence, it 

 would seem, the decomposition products of the proteids exert 

 a protective influence. 



Hydrogen peroxide has an energetic action upon pure ricine, 

 but is only slightly injurious to the impure substance. 



Alcohol does not dissolve ricine and does not injure it. 



Ricine appears to be absolutely indiffusible, as was first shown 

 by STILLMARK. 



Action of Ricine. Ricine has two of the most important pro- 

 perties of toxines extraordinarily great activity and a period 

 of incubation; but, on the other hand, does not show their 

 strictly specific action. Hitherto no animal has been found that 

 is completely immune against ricine, but the susceptibility is not 



1 Tichomiroff, " Ueber die Fallg. v. Toxalbuminen durch Nuclei'nsaure," 

 Zeit.f. phyaiol. Chem., xxi., 90, 1895. 



