202 THE TOXINS PRODUCED BY BACTERIA 



always associated with a given amount of disease effect, though 

 a process of elimination of waste products must be all the time 

 going on in the animal's body. Again, too much importance 

 must not be attached to loss of toxicity by toxins at relatively 

 low temperatures. This is not true of all toxins, and further- 

 more many proteids show a tendency to change at such 

 temperatures ; for instance, if egg albumin be kept long enough 

 at 55 C. nearly the whole of it will be coagulated. We must 

 therefore maintain an open mind on this subject. 



Similar Vegetable and Animal Poisons. It has been found that 

 the bacterial poisons belong to a group of toxic bodies all present- 

 ing 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 communis and the Alms 

 precatorius (jequirity) respectively. From the Eobinia pseudacacia 

 another poison robin belonging to the same group is obtained. The 

 chemical reactions of ricin and abrin correspond to those of the bacterial 

 toxins. 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 active poisons known ricin being the more powerful. When they 

 are 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 nrncous membranes, 

 abrin especially being capable of setting up most acute conjunctivitis. 

 In the action 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 hsemolytic 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 



