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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 
spiders 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 depends. 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.t 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 
Effects on 
Insects. 
Cam- state of imsensibility, and is available as fresh food for some 
eee hours and perhaps for several days. I do not know upon 
Opinion. pene as GP 
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 are 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 perhaps more frequently omitted than given, the insect being 
1 Spiders of Dorset, Introduction, page xxv. 
