194 THE TOXINS PRODUCED BY BACTERIA 



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 beiDg capable of setting up most acute conjunctivitis. 

 In the action of a poisonous fungus, Amanita likalloides, a similar 

 toxin is at work. After an incubation period of some hours, symptoms of 

 abdominal pain, diarrhrca with bloody stools, and, later, jaundice occur. 

 In vitro the toxin has a hemolytic action. Like other poisons of this 

 class, an antitoxin can be produced towards the fungus poison. 



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

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

 are usually called venins, and a very representative group of such venins 

 derived from different species has been studied. To speak generally, 

 there is derivable from the natural secretions of the poison glands a 

 series of venins which have all the reactions of the bodies previously 

 considered. Like ricin and abrin, they are not so easily dialysable as 

 bacterial toxins, 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, and some will stand 

 boiling. There is also evidence that in a crude venin there may be several 

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

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

 are almost immediate. An outstanding feature of the venins is the 

 complexity of the crude poison secreted by any particular species of 

 snake. C. J. Martin, in summing up the results of many observers, has 

 pointed out that different venoms have been found to contain one or 

 more of the following poisons : a neurotoxin acting on the respiratory 

 centre ; a neurotoxin acting on the nerve- endings in muscle ; a toxin 

 causing haemolysis; toxins acting on other cells, e.g., the endothelium of 

 blood vessels (this from its effects has been named hsemorrhagin), 

 leucocytes, nerve-cells ; a toxin causing thrombosis ; a toxin having an 

 opposite effect and preventing coagulation ; a toxin neutralising the 

 bactericidal qualities of the body fluids and thus favouring putrefaction ; 

 a toxin causing agglutination of the red blood corpuscles ; a proteolytic 

 ferment ; a toxin causing systolic standstill of the excised heart. Any 

 particular venom contains a mixture in varying proportions of such 

 toxins, and the different effects produced by the bites of different snakes 

 largely depend on this variability of composition. The neurotoxic, the 

 thrombotic, and the hsemolytic toxins are very important constituents 

 of any venom. The toxicity of different venoms varies much, and no 

 general statement can be made with regard to the toxicity of different 

 poisons towards man. Lamb calculated that the fatal dose of crude 

 cobra venom for man is probably about - 015 of a gramme, and that 

 if such a snake bites with full glands many times this dose would 

 probably be injected, but, of course, the amount emitted depends largely 

 on the period which has elapsed since the animal last emptied its glands. 

 When a dose of a venom not sufficient to cause immediate death from 

 general effects be given, very rapid and widespread necrosis often may 

 occur in a few hours round the site of inoculation. 



An extremely important fact was discovered by Flexner and Noguchi, 

 namely, that the haemolytic toxin of cobra venom in certain cases has no 

 action by itself, but produces rapid solution of red corpuscles when some 

 normal serum is added, the latter containing a labile complement-like 

 body, which activates the venom. In this there is a close analogy to 



