20 PASTORAL AND AGRICULTURAL BOTANY 



that the toxic properties of ricin are associated inseparably with the co- 

 agulable albumin of the castor beans, and were able to isolate this toxal- 

 bumin in such purity that one one-thousandth of a milligram (o.oooooi 

 gram) was fatal per kilo of rabbit and solutions of o.ooi per cent would 

 agglutinate red corpuscles. The phytotoxins have been used extensively 

 in the investigation of immunity, since they obey the same laws as bac- 

 terial toxins. They seem to possess haptophore and toxophore groups 

 and immunity is readily obtained against them. The immunity is speci- 

 fic, ricin antitoxin, for example not protecting against abrin. 



Their poisonous action is manifested in agglutination of the erythro- 

 cytes, local cellular destruction, and in hemolysis. Such toxalbumins 

 as crotin and phallin are actively hemolytic, that is the hemoglobin escapes 

 from the stroma of the blood corpuscles into the surrounding fluid. Ricin, 

 abrin and robin are more marked by their agglutinating action, hemolysis 

 being produced only by relatively large doses. They resemble the bac- 

 terial toxins, in that immunity can be secured against them, and the 

 immune serum will prevent their hemolytic action. The hemolytic, 

 or agglutinating, action of these toxalbumins, except phallin, is not de- 

 stroyed by exposure to 65 to 7oC. of heat, but iooC does destroy it. 

 The action of these substances is not like that of the enzymes in being 

 quantitative, a given amount acting on a given amount of corpuscles to 

 which it is bound. 



Another quite distinct group of vegetable hemolyzing agents are the 

 saponin substances closely related to the glucosides and found as strong 

 protoplasmic as well as hemolytic poisons. They differ from the true 

 toxins in being resistant to heat, having no resemblance to proteins and 

 do not give rise to antibodies on immunization of animals. The degree of 

 their toxicity is not directly proportional to their hemolytic activity for 

 they seem to chiefly injure the nerve-cells. Apparently hemolysis is 

 brought about by action on the lipoids of the red corpuscles, for addition 

 of cholesterol to saponin prevents its hemolytic effect. Kobert has 

 shown that all cause hemolysis, some in dilutions as great as i : 100,000. 

 The following are the most important members of this group: sapotoxin 

 obtained from Quillaja, cyclamin from Cyclamen, solanin from members of 

 the potato family, helvellic acid from fungus Helvetia esculenta, phallin 

 from toadstool, Amanita phalloides. 



Applicability of Ehrlich's Theories. As the theory of Ehrlich is applic- 

 able in the study of the activity of such toxins and the immunization of 



