EFFECTS AND USES OF SPIDER POISON. Pata 
UIE 
From the indications of anatomy we turn to the testimony of natural- 
ists and other observers of the effects of spider venom. First in order of 
value, for their extent and thoroughness, are the experiments of Mr. Black- 
wall, an abstract of which I present. The experi- 
menter induced a female Epeira diademata to bite him 
on the inside of the left hand, near the base 
of the fore finger. It continued to force its 
fangs deeper into the flesh, during a period 
of many seconds, and at last quitted its hold volunta- 
rily, when a little blood issued from the wound. Though 
the spider was in a state of great excitement from pre- 
vious irritation, Mr. Blackwall did not experience more Pee: 
’ is Fic, 246, The poison gland, 
inconvenience from its bite than from a puncture made  auct, and fang of Neme- 
near it at the same time with a fine needle. The ef- eee nas ees 
fects of both injuries appeared to be very similar. 
Again, a highly exasperated female Diademata was allowed to seize 
him on the inner side of the left fore arm near the carpus. It continued 
for more than a minute to bury its fangs deeper into the flesh, 
Effect of and, on quitting voluntarily, a little blood flowed from the wound- 
ee ed part, near which a puncture was made simultaneously with 
ite. : ; = 
a fine needle. The effects of this and the preceding experiment 
were alike. In both cases the air was sultry and the temperature as high as 
seventy-five degrees. ‘These two wounds were inflicted in the month of July. 
In the latter part of August, a powerful 
and much irritated female Epeira quadrata bit 
Mr. Blackwall on the inner side of the left 
fore arm near the carpus. It retained its hold 
for the space of five minutes, occasionally fore- 
ing its fangs deeper into the flesh, and, on quit- 
ting it voluntarily, blood issued freely from the 
punctures. The effects of this bite did not dif- 
fer materially from those of a wound made at 
the same time with a needle of average size, 
the intensity and duration of pain being very 
similar in both instances. 
a ee During the same month spiders of various 
Tarantula. X 2. (From nature.) Species were induced, under the influence of ex- 
Ue oan Giekteaee cited feelings, to seize a piece of clean window 
andthe openinginthefangsthrough glass with their fangs, when a transparent fluid, 
ee which escaped from the small aperture near their 
extremity, was deposited upon it. The application of this fluid to the tongue 
did not produce any sensible effect upon that organ. 
1 Linn. Trans, Vol. SS; pages 31-37. 
Hvidence 
of Effects. 
Re % “ 
