80 SCORPIONS 



killed by the mongoose — indeed, few species are devoid of pre- 

 datory enemies. Nevertheless, the existence of poison, coupled 

 with the presence of aposematic sound production, will deter 

 many potential enemies, thereby imparting an evolutionary ad- 

 vantage to their possessors. 



Poison 



The poison of scorpions has attracted attention since earliest 

 times and observations as to its effects on man and other verte- 

 brates have often been made. Unfortunately these have been some- 

 what conflicting and scientifically accurate data has been obtained 

 only comparatively recently. One source of error has been lack of 

 knowledge of the physiological state of the animal on which the 

 observation was made, of the quantity of poison injected by the 

 scorpion into the wound and its relation to the total weight of the 

 victim. Another has been inaccurate and uncertain determinations 

 of the species of scorpion, for it is known that different species 

 vary greatly in the degree of virulence and type of their poison. 

 Exact knowledge can be obtained only under carefully controlled 

 laboratory experiments which may be supplemented by field ob- 

 servations provided that the scorpion is identified by an expert. 

 Such observations have led to the conclusion that at least two 

 types of poison exist. One of these is local in effect and compara- 

 tively harmless to man: it is exemplified by the European Eus- 

 corpius italicus and the American Centruroides vittatus. The other 

 type is neurotoxic resembling some kinds of snake venom and can 

 be extremely dangerous. It is found in Buthus occitanus and An- 

 droctonus australis in North Africa and in Centruroides sculpturatus 

 and C. gertschi in North America. Poison for experiments may be 

 obtained in pure form without injury to the scorpion by electrical 

 stimulation. It has been found that B. occitanus of southern France 

 produces at one time about 8 mg of fluid poison: curiously enough 

 the same species from North Africa is said to be much more 

 dangerous, while the sting of A. australis has been known to kill a 

 man in about four hours, a dog in seven minutes and has a toxicity 

 almost equal to that of a cobra. 



The symptoms caused by scorpion poison of the less virulent 

 type consist mostly of sudden sharp pain followed by numbness of 



