178 MICROBES AND TOXINS 



to be done with caution). With small equal repeated doses, 

 tuberculin behaves like a poison towards which the tuberculous 

 patient becomes more and more sensitive. 



Cutaneous Reactions. — A drop of very dilute tuberculin, 

 applied by means a prick or very superficial scarification on the 

 non-tuberculous skin of a tuberculous subject, excites at the 

 point a reaction which may extend to the vessels and lympathic 

 glands of the neighbourhood — -V. Pirquet's experiment ; this 

 represents a new diagnostic procedure, the cuti-reaction. It has 

 been modified and perfected by dropping the tuberculin between 

 the eyelids {conjunctiva or oculo-reaction of Wolff-Eisner and of 

 Calmette) or by inoculating it with a very fine needle in the 

 depths of the skin itself (the intra-dermo-reaction of Mantoux). 



It is a reaction of extreme interest, for it occurs at a non- 

 tuberculous point, i.e., a point containing no bacilli, in a 

 tuberculous individual ; and can only be explained by suppos- 

 ing that the whole body has become impregnated with sub- 

 stances formed under the influence of the tubercle bacillus. 



Animal Toxins — The Venoms ^ 



In the struggle for existence, certain animal species have 

 acquired, as their means of attack and defence, organs which 

 secrete and inoculate toxic substances. These animal toxins 

 are the venoms, and such venoms are known at almost every 

 level in the animal scale. 



Venoms in the Animal 'World Among the Coelen- 



terata the Actinians produce certain poisons which can be 

 extracted from their tentacles, thalassine and congestine, well 

 known as having formed the subject of Ch. Richet's experi- 

 ments on anaphylaxis. These poisons are perhaps the cause of 

 the disease of sponge-fishers, who dive quite naked without a 

 diving-suit ; the disease consists in burning of the skin and 

 swelling, with gangrene and violent fever. 



The pedicles of the Sea-Urchins (Echinoderms) contain a 



^ Vide papers of Noguchi and Calmette. 



