12 



Poisonous Arthropods 



"The tarantulas, no matter how often they were placed on the 

 skin, handled, and irritated, could not be induced to bite either myself, 

 the janitor, or the ordinary experimental animals. The objection 

 that the tarantulas were weak and indifferent cannot stand, for as 

 soon as I placed two of them on the shaved skin of a rabbit, instead of 

 an attack on the animal, there began a furious battle between the 

 two spiders, which did not cease until one of the two was killed." 



"Since the spiders would not 

 bite, I carefully ground up the 

 fresh animals in physiological 

 salt solution, preparing an extract 

 which must have contained, in 

 solution, all of the poisonous 

 substance of their bodies. While 

 in the case of Latrodectus, as we 

 shall see, less than one specimen 

 sufficed to yield an active extract, 

 I have injected the filtered extract 

 of six fresh Russian tarantulas, 

 of which each one was much 

 heavier than an average Latro- 

 dectus, subcutaneously and into 

 the jugular vein of various cats 

 without the animals dying or 

 showing any special symptoms. 



On the basis of my experiments I can therefore only say that the 

 quantity of the poison soluble in physiological salt solution, even 

 when the spiders are perfectly fresh and well nourished, is very 

 insignificant. That the poison of the Russian tarantula is not 

 soluble in physiological salt solution, is exceedingly improbable. 

 Moreover, I have prepared alcoholic extracts and was unable to 

 find them active. Since the Russian spider exceeds the Italian in 

 size and in intensity of the bite, it seems very improbable to me that 

 the pharmacological test of the Italian tarantula would yield 

 essentially other results than those from the Russian species." 



To the Avicularoidea belong the largest and most formidable 

 appearing of the spiders and it is not strange that in the New World 

 they have fallen heir to the bad reputation, as well as to the name of 

 the tarantula of Europe. In this country they occur only in the 

 South or in the far West, but occasionally living specimens are brought 



7. Trochosa singoriensis. After Kobert. 



