Neurotoxins, Trichotoxins, etc. 25 



Neurotoxins are another class of antibodies obtained by injecting the brain- 

 substance of one species into another. Metchnikoff succeeded in obtaining 

 a neurotoxin for pigeons in the serum of rats treated with pigeon-brain emulsion. 

 His pupil Delezeune (x. 1900, p. 696), who cites the unpublished experiment, 

 subsequently obtained dog neurotoxin by treating a duck with dog-brain substance. 

 He (p. 703) tested this neurotoxin on rabbits with negative result, whereas 

 it affected cats, though less than dogs. This indicates a relationship between these 

 Carnivores, such as I have been able in a measure to demonstrate by means 

 of pi'ecipitins. Again as with the precipitins (see later) he was unable to obtain 

 positive results by repeatedly injecting rabbit-brain substance into guinea-pigs 

 (p. 695). Boeri (28, x. 1902) on the other hand states that he injected rabbit- 

 brain emulsion intraperitoneally into guinea-pigs, and found their serum when 

 injected subdurally into rabbits to pi'oduce prolonged nervous excitation. When 

 heated to 55° C. the serum had no such effect. 



Neurotoxins are normally present in venoms of ser^jents, as found by Flexner 

 and Noguchi (1902). The neurotoxin is distinct from the haemolytic substance 

 in venom, for a venom, robbed of its haemolysin hy the addition of coi-puscles, was 

 neurotoxic, and vice versa. This agrees with Ehrlich's view, as supported, amongst 

 others, by Wassermann and Takaki's experiments upon the fixation of tetanus 

 toxin in certain centres, etc. 



Trichotoxins were first obtained by von Dungern (1899), the antibody, as the 

 name implies, exerting a special effect upon ciliated epithelium. He injected 

 rabbits and guinea-pigs with the tracheal epithelium of the ox, and found their 

 serum to immobilize the ox ciliated epithelium. He however found that the 

 antiserum also haemolysed ox corpuscles, but it had more affinity for the epithelium 

 than did an antiserum obtained by corresponding blood injections. Rabbits 

 injected with cows' milk gave an antiserum which also immobilized the epithelium, 

 and it was also haemolytic to a considerable degree. The three antisera (for milk, 

 coi'puscles, epithelium) were subjected to comparative tests on 5 *^/q blood corpuscle 

 suspensions, the antisera being inactivated and then reactivated by the addition 

 of complement. The results showed differences with i-egard to the haemolytic 

 properties, those of the antisera for milk and epithelium being distinct from the 

 third, but indistinguishable from each other. 



Other authors have finally claimed to have jjroduced a variety of toxic substances 

 in animals treated with emulsions of different glands, this being at present the 

 subject of much active investigation. It is only necessary to mention a few of 

 these so as to indicate the general drift of the work. Lindenmann (ii. 1900, p. 57) 

 treated guinea-pigs with rabbit kidney-emulsion, obtaining, he claims, a highly 

 potent " nephrotoxin " which caused necrosis and profoimd disintegration of the 

 epithelium of the convoluted tubules in the rabbit's kidney, the glomeruli I'emaining 

 unaffected. Nefedieff" (25, r. 1901, p. 18) repeated the experiment, and reversed 

 it, confirming the result. He found the nephrotoxin to be also haemolytic. 



Delezenne (viii. 1900) obtained antisera for liver cells, or " hepatotoxiiis," and 

 these have also been studied by Deutsch (cited by Nefedieff). Mankowski (1902) 

 treated cats with intraperitoneal injections of dog thyroid gland emulsion, obtaining 

 a serum having toxic properties for the gland in dogs, the action being in the main 

 thyreolytic. The serum containing the ^'' thyreotoxin" could be inactivated and 



