1890.] ` Proceedings of Scientific Societies. 1221 
bite, a man having died in twelve hours after being bitten by one. 
That the poison was useful to the spider in killing its prey was unques- 
tioned, but that it was powerful enough to cause the death of a man 
was considered doubtful. The mandibles are hollow, and from aper- 
tures near the end the poison is ejected. This poison is contained in 
a poison sac lying above. It varies in shape in different species, and 
is squeezed out by muscular contraction. The gland in the genus 
under consideration is very small, averaging 2 mm. long and 2 mm. 
wide, with a capacity of .o7 cubic mm. The poison is clear, viscid, 
and has an acid reaction. It frequently becomes turbid. It will not 
mix with water, but remains in the form of granules. 
Latrodectus lives under stones, and spins no web. Unlike most 
spiders, it drinks no water, and has a great dislike of it. If a drop 
be placed upon its back it goes almost into spasms, and for hours 
afterwards tries to brush the water off. Water destroys the poisonous 
«qualities of the poison. In pursuing its prey in a glass jar it was seen 
to crawl up the sides and from its spinnerets eject several drops of a 
viscid fluid. The prey having been bitten, is left, and the spider 
returns and devours the fluid previously ejected. As to the poisonous 
effects of spiders’ poison, it was stated that a rice bird died in seven- 
teen seconds after having been bitten by the Mygale, or bird-catching 
spider. Another died in thirty seconds. Experiments to test the 
poison of Latrodectus were all negative, neither a rabbit, a guinea- 
pig, nor a mouse being affected in the slightest. The idea that spiders 
of this genus are capable of inflicting bites severe enough to be harm- 
ful is very widespread, but Dr. Marx regarded it as a superstition.with 
little real foundation. 
Dr. C. V. Riley stated that he believed there was some truth in the 
accounts of injury by spider-bites. Some cases are too well authen- 
ticated to be doubted. He referred to the different effects a bite or a 
sting might have upon different persons, and while one would be unaf- 
fected, another might be very seriously poisoned. He spoke of a 
friend who was at one time noted for his skill in handling bees, and 
he was never stung. But on one occasion he was stung, and so 
severely that he came near dying. After that he could not go near 
the bees without being stung and being poisoned by it. 
Dr. Theobald Smith stated that the effect of poison was somewhat 
analogous to that produced by bacteria. It was commonly supposed 
that diseases were caused by the rapid and excessive multiplication of 
bacteria. This seems to be a mistake, and it is to a poison produced 
during the increase of the bacteria that the ill effects are due. Ani- 
