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HARDWICKE'S SCIENCE-GOSSIP. 



[Dec. 1, 186' 



/. 



FANGS OE SPIDERS. 



"The point envenom'd too! 

 Then, We.vham, to thy work ! " 



Hamlet, Act v., Sc. ii. 



"TVTO character so bad but an apologist may be 

 -'-* found for it : those wily murderers the 

 spiders Lave an advocate in " E. T. S.," who is 

 retained to prove them innocent of all poisonous 

 intention or ability. But the case is a bad one ; for 

 the criminating evidence— both direct and circum- 

 stantial—is overwhelming. 



As a modest witness for the prosecution, permit 

 me to state briefly what I have done aud seen, aided 

 by that able detective, Wenham's Binocular. I took 

 a female garden spider (Epeira diadema), soaked it 

 in weak spirit and water for a fortnight ; drew the 

 mandibles from their half-rotten attachment, and 

 found, protruding from each basal joint, broken 

 filaments of muscle, and the rounded end of a large 

 gland. I then broke up a portion of the horny 

 integument of one mandible, and easily detached 

 most of the muscle, leaving the glandular sac 

 attached by a thread or duct to the fang, in the 

 interior of which it could be traced for some 

 distance. "From information I had received 

 (Mic. Die., art. ' Arachnida'), I expected to find 

 the poison-bag encircled by muscular bands, and, 

 indeed, so found it ; the fibres coiling spirally and 

 very regularly round it. The other inaudible was 

 immersed in a solution of caustic potash, which 



Fig. C82. Fang and poison-baa: of Spider 

 a. point x SOU. 



50 ; 



destroyed all the soft parts, but cleared the fang 

 sufficiently to allow an evident orifice to be detected 

 near the point, and an internal channel therefrom 

 to be faintly indicated. 



I next bought a very large spider (species 

 unknown to me) at Gardner's, in Holborn, and in 

 its enormous fang saw the expected hole so plainly 

 and of such a size that I immediately thought of 

 "E. T. S./' aud how completely he had "put his 

 foot in it ! " 



The aperture is not merely an oval slit, as it is 

 generally figured, but the side towards the point is 

 deeply bevelled, thus facilitatiug the emission and 

 direction of the venom. 



"E.T. S." does not mention on what species he has 

 made experiment, which is an important omission, 

 as it is quite possible that all spiders may not be 

 venomous. Now, if your correspondent still remain 

 incredulous, as is very likely, pray let him call on 

 me, and he shall have proof the most certain, — proof 

 ocular and proof binocular. 



24, Cor /dill. Henry Davis. 



The same subject has brought us the following 

 remarks by another correspondent : — 



"E. T. S." reopens a question which I thought 

 had been settled, in its main features, by the com- 

 munications that have already appeared in your 

 columns. He objects that he cannot find the 

 poison-bag of the spicier nor see the orifice in the 

 fang ; and he cannot understand how the poison 

 could be expressed from the end of a " closed sac." 

 I can assure your correspondent that the unsatis- 

 factory results of his experiments are due to defective 

 manipulation. The spider to be operated upou 

 should be soaked in water for forty-eight hours. 

 The secoud joint of one of the mandibles may then 

 be seized laterally with the forceps, and pulled from 

 the head. The jaws will come away together, and 

 the two poison-bags will be exposed, the broad 

 ends being free, and the narrow ends still attached 

 within the fangs. If it be desired to get the entire 

 bag with the extreme point of its neck, the spider 

 must be left in soak for a longer time. The poison 

 gland I have not seen ; indeed, I have not looked 

 for it ; but there is little doubt that it lies imme- 

 diately behind, and is attached to the broad end of 

 the bag. I think I can see the mark of the attach 

 ment. These bags vary in size ; a mounted one 

 which I have just measured is about one-twelfth of 

 an inch in length, exclusive of the neck or duct. 

 They are clearly membranous, and are covered with 

 bands of striated muscle obliquely disposed. There 

 is therefore no difficulty in understanding how the 

 poison is expressed from the bag, which it will be 

 seen is not quite accurately described as a " closed 

 sac." Wc are told that in the case of the poisonous 

 snakes the immediate cause of the emission of the 

 venom is purely mechanical, the erection of the 

 fang creating a pressure upon the reservoir ; but I 

 do not think there is any similar arrangement in the 

 spider. And this, taken in connexion with the dis- 

 position of the striated muscle, suggests an iute- 



