EFFECTS AND USES OF SPIDER POISON. 279 



Mr. Blackwall then directed his attention to the effects of spider wounds 

 upon insects. His observations were made upon a number of genera of 

 s})iders in their assaults upon such insects as wasps, bees, flies, 

 _ and grasshoppers. The result of these observations, which are 



recorded in considerable number, is that all these insects sur- 

 vived after the infliction of the spider's stroke for a period of time, in 

 some cases, as high as three days. 



The experiments did not present any facts which appear to sanction 

 the opinion that insects are deprived of life much more quickly when 

 pierced by the fangs of spiders than when lacerated mechanically to an 

 equal extent by other means, regard being had in both cases to the vitality 

 of the part injured — a circumstance upon which the suddenness of death 

 largely de})ends. It is true that the catastrophe is greatly accelerated if 

 spiders maintain a protracted hold of their victims. But this result is 

 attributable to the extraction of their fluids, which are transmitted, by oft 

 repeated acts of deglutition, into the stomach. 



Mr. Cambridge does not hesitate to say that the bite of a spider is 

 undoubtedly poisonous when inflicted upon its prey.^ And he supposes 

 that at least one effect of the bite in most cases is to benumb or par- 

 alyze the insect, which, if not at once devoured, remains in a 

 Cam- g^^^^g q£ insensibility, and is available as fresh food for some 

 ^ . . hours and perhaps for several days. I do not know upon 



what grounds this distinguished arachnologist bases this opinion, 

 as he gives no facts bearing upon the matter, and qualifies his opinion by 

 the word "probably." Perhaps he has reasoned from the analogy of the 

 effect of a wasp's sting upon a spider, which is precisely that which he 

 supposes to result to the victim of the spider's bite. But analogy is not 

 argument, and while it may guide us to a safe conclusion, cannot be 

 received as a sufficient demonstration in a matter of this sort. 



For myself, I may say that I have never seen a single case that would 

 justify Mr, Cambridge's conclusion. It is undoubtedly difficult to make a 

 decisive observation, because in the case of Sedentary spiders, the habit of 

 swathing the prey in a thick shroud of white silk prevents one from ob- 

 serving whether the stroke of the spider's fangs has produced any special 

 effect. This swathing is done so rapidly, and the limbs and wings of an 

 insect arc so effectually wrapped up, that it needs no suggestion of par- 

 alyzing venom to account for the creature's utter immobility. Moreover, 

 I have often seen insects struggling within their enswathment a little 

 while after they had been captured. 



Nor is it the unvarying custom of Sedentary spiders to strike their 

 victims when they capture them. My observations convince me that the 

 stroke is ))orliaps more froquontly omitted than given, the insect being 



* Spiders of Dnrpot, TntmrUiction, page xxv. 



