242 SCIENCE PROGRESS. 



albumose. He found that these bodies, as Stillmark (41) 

 had shown was the case with ricin, possessed marked 

 toxic properties which were wholly destroyed by boiling ; 

 the introduction of ricin by intravenous injection pro- 

 duces multiple thrombi, due to the clinging tog-ether of 

 red blood corpuscles. By feeding mice with biscuits, to 

 which ricin is added in known quantities, after a certain 

 time, from one to two weeks, a condition of immunity 

 to ricin injection is established, and this lasts for six to 

 seven months. He further estimates the grade of immunity 

 which is reached, by calculating that if 1 c.c. of a solution, 

 1 : 200,000 per 20 grammes body weight is the lethal dose 

 of ricin, then if the animal withstands 1 c.c. of 1 : 500, then 

 its immunity grade would be 400. In the blood of animals 

 treated in this way and which are immune, or rather toxine- 

 resistant, a body termed anti-ricin is present, and by the in- 

 troduction of the serum of ricin-immune animals into others 

 a relative degree of immunity is conferred. For robin (a tox- 

 albumin from the bark of the acacia) the same statement holds 

 good, and also for abrin ; but the anti-bodies of any one will 

 not annul a lethal dose of any of the other toxic bodies. A 

 solution of abrin 1 : 100,000 is fatal for mice when 1 c.cm. 

 per 20 grammes body weight is injected. By feeding with 

 gradually increasing quantities of abrin these animals be- 

 come highly immune, and this immunity can be inherited by 

 the offspring. This condition might be due either to heredity 

 in the ontogenetic sense or by the influence of hypothetical 

 immunity-conferring bodies yielded by the mother directly 

 to the foetus. In attempting to decide this matter it was 

 shown by Ehrlich that the progeny of highly immune 

 fathers and normal mothers showed no immunity, but were 

 actually rather more sensitive than control animals, and 

 therefore an idioplasm of the sperm is not capable of 

 causing a transference of immunity, and, indeed, since the 

 immunity was acquired, this result was to be expected. 

 With immune mothers and susceptible fathers positive 

 results were obtained, for as long as a month after birth 

 a well-marked resistance to many times the lethal dose of 

 abrin was evident. This resistance gradually diminishes 



