160 THE TOXINES PRODUCED BY BACTERIA. 



Similar Vegetable and Animal Poisons. Within recent years it has 

 been found that the bacterial poisons belong to a group of toxic bodies 

 all presenting very similar properties, other members of which occur 

 widely in the vegetable and animal kingdoms. Among plants the 

 best known examples are the ricin and abrin poisons obtained by 

 making watery emulsions of the seeds of the Ricinus comtmtnis and 

 the Abrus precatorius (jequirity) respectively. From the Robinia 

 pseudocode another poison robin belonging to the same group is 

 obtained. The chemical reactions of ricin and abrin correspond to 

 those of the bacterial toxines. They are soluble in water, they are 

 precipitable by alcohol, but being less easily dialysable than the 

 albumoses they have been called toxalbumins. Their toxicity is 

 seriously impaired by boiling, and they also gradually become less 

 toxic on being kept. Both are among the most powerful poisons 

 known ricin being the more fatal. When injected subcutaneously a 

 period of twenty-four hours usually elapses whatever be the dose 

 before symptoms set in. Both tend to produce great inflammation at 

 the seat of inoculation, which in the case of ricin may end in an acute 

 necrosis ; in fatal cases hsemorrhagic enteritis and nephritis may be 

 found. Both act as irritants to mucous membranes, abrin especially 

 being capable of setting up most acute conjunctivitis. 



It is also certain that the poisons of scorpions and of poisonous 

 snakes belong to the same group. The poisons derived from the 

 latter are usually called venenes, and a very representative group of 

 such venenes derived from different species has been studied. To 

 speak generally there is derivable from the natural secretions of the 

 poison glands a series of venenes which have all the reactions of the 

 bodies previously considered. Like ricin and abrin, they are not so 

 easily dialysable as bacterial toxines, and therefore have also been classed 

 as toxalbumins. Their properties are also similar ; many of them are 

 destroyed by heat, but the degree necessary here also varies much. 

 There is also evidence that in a crude venene there may be several 

 poisons differently sensitive to heat. All the venenes are very powerful 

 poisons, but here there is practically no period of incubation the effects 

 are almost immediate. The toxicity of the venenes varies much with 

 the animal employed, but chiefly with the species of snake from which it 

 was derived. For instance, .47 milligrammes of crude venene from the 

 Indian cobra will kill a rabbit in three to four hours. In the case of 

 the American rattlesnake the dose would be 3.5 milligrammes, and in 

 that of the Australian hoplocephalus variegatus 2.5 milligrammes. The 

 general effects of these vary with the dose, and slight variations also 

 exist between the effects of venenes of different snakes. Thus cobra 

 poison is said to produce rapid paralysis of the lips, tongue, larynx, and 

 respiratory apparatus, from which death results. On the other hand 

 the venene of the daboia of Ceylon is said to cause violent general 

 convulsions, succeeded by paralysis, but with very little respiratory 

 affection. In the case of a dose not sufficient to cause immediate 



