VENOMS IN THE ANIMAL SERIES 279 



On the other hand, it lias been shown by the investigations of 

 C. Nicolle and G. Catouillard that the same antivenomous serum 

 has no effect upon the much weaker venom of the scorpion of 

 Tunis {Heterometrus maurus), which, in the case of man and 

 mammals in general, scarcely does more than produce a transient 

 oedema at the point of inoculation. 



The venom of Heterometrus maiirus is, however, toxic enough 

 to the sparrow. When one of these little birds is inoculated in 

 the pectoral muscles with the contents of the poison-glands of a 

 single scorpion belonging to this species, the following symptoms 

 are observed : Immediate rigidity, doubtless connected with the 

 pain, then, after a few seconds, depression and relaxation of the 

 muscles. The bird remains upright, but its body sinks down more 

 and more until it comes into contact with the ground ; if on a 

 perch, it soon becomes unsteady and drops off. There is dyspnoea, 

 which any effort increases, and death supervenes suddenly ; all at 

 once the sparrow falls on its side, stiffens, sometimes has a few 

 convulsions, and then finally becomes still. The time occupied by 

 these phenomena is always short, although it varies from two 

 minutes to half an hour. 



Scorpion-venom is a strong irritant to the mucous membranes. 

 When dropped into the eye of a rabbit it produces acute ophthalmia. 



It has often been asserted that scorpions kill themselves with 

 their own venom if enclosed in a circle of fire. This is an absolute 

 myth, for it is easy to prove by experiment, as was done by Bourne 

 at Madras,^ that these animals cannot be intoxicated by their own 

 poisonous secretion, nor by that of other individuals of the same 

 species. Moreover, it has been established by Metchnikoff," in 

 very definite fashion, that the blood of the scorpion is antitoxic. 

 If O'l c.c. of this blood be added to a dose of venom lethal to mice 

 in half an hour, a mouse injected with this mixture resists inde- 

 finitely. This antitoxic power is exhibited both by Scorpio afer 

 and the Algerian Androctonus. 



' Proceedings of the Boyal Society, vol. xlii., 1887, p. 17. 

 - " L'immunite dans les maladies infectieuses," Paris, 1901. 



