VEGETABLE AND ANIMAL TOXINS 197 



In the actiou of a poisonous fungus, Amanita phalloides, a similar 

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

 abdominal pain, diarrhoea with bloody stools, and later jaundice occur. In 

 vitro the toxin has a haemolytic action. Like other poisons of this class, 

 an antitoxin can be produced towards the fungus poison. 



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 venins, ana 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 venius 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 neurotoxiu 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 ha-morrhagin), 

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

 opposite effect and preventing coagulation, a toxin neutralising the 

 I'.K tericidal 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 excited 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 haemolytic 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 has 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 

 what holds in the case of a haemolytic serum deprived of complement by 

 heat at 55 C. (p. 130). Kyes and Sachs further showed that in addition 

 to serum-complement a substance with definitely known constitution, 

 namely lecithin, had the property of activating the haemolytic substance 

 in cobra venom, the two apparently uniting to form an actively toxic 



