VENOMS IN THE ANIMAL SERIES 279 
On the other hand, it has 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 
cedema at the point of inoculation. 
The venom of Heterometrus maurus 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 0:1 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. 
1 Proceedings of the Royal Society, vol. xlii., 1887, p. 17. 
2 & T/immunité dans les maladies infectieuses,” Paris, 1901. 
