Scientific Proceedings. ( t 43) 79 



arterial tension which it causes, cannot be determined from these 

 experiments. This question of etiology must be settled by other 

 methods of investigation. The chief value of the studies herein 

 briefly summarized lies in the application of this comparatively 

 simple series of changes to the more complicated vascular lesions 

 occurring in the arteriosclerosis of man. 



39 (85). " On the chemical and physiological properties of 

 ricin," with demonstrations: THOMAS B. OSBORNE and 

 LAFAYETTE B. MENDEL. 



A chemical study of the castor bean has indicated that this 

 seed contains proteins of the same character as the other oil-seeds 

 which have been examined, namely, (1) a considerable quantity of 

 a globulin which can be obtained in octahedral crystals ; (2) a 

 much smaller quantity of an albumin, coagulating at about 60 0 C. 

 to 70 0 C, the temperature at which it separates depending to a 

 large extent on the rate of the heating and other conditions ; (3) 

 proteoses which appear to belong to several of the now recognized 

 groups of this class of substances. The satisfactory separation of 

 the various types of proteins was accomplished largely by the use 

 of fractional salt precipitation and dialysis. 



The toxic constituent of the castor bean has been investigated 

 under Robert's guidance by Stillmark, who applied the name ricin 

 to protein material which he separated. The product which Still- 

 mark regarded as relatively pure must have been a mixture of 

 proteins and have contained only a small proportion of the toxic 

 compound. Cushny made a more careful study of ricin and ob- 

 tained a substance of sufficient toxicity to produce death in animals 

 with a dose of 0.04 mg. per kilo of body- weight. He regarded the 

 toxic compound as protein in nature. Among subsequent investi- 

 gators, Jacoby has denied the protein character of ricin. He di- 

 gested his toxic preparations with trypsin and obtained solutions 

 which retained their toxicity although apparently no longer giving 

 protein reactions. Brieger, however, failed to prepare toxic prepar- 

 ations free from protein material. 



The efforts of the authors have been directed especially to the 

 possibility of isolating the toxic constituent of the castor bean and 

 determining its chemical nature. The toxic action has been found 

 to be associated wholly with the preparations containing the coagu- 



