86 ENTOMOLOGICAL SOCIETY 



The first experiment consisted in the inoculation of a pair of 

 unbroken poison glands into the region of the groin of the 

 rabbit. An incision was made through the previously shaved 

 off epidermis and the underlying adipose tissue to the muscles ; 

 then the poison bags were introduced and left intact for ab- 

 sorbtion. The result was negative ; the rabbit continued to 

 eat its food in ten minutes after the operation, and lived for 

 over two weeks in perfect health, when it was used by one of 

 the scientists of the Bureau of Animal Industry for other ex 

 periments, during which it died. The post-mortem examina 

 tion of the infected part showed a hardly noticeable external 

 scar, while the location of the deposition of the poison bags 

 showed a slightly reddened area. 



The next experiments were made with three Guinea pigs. 

 Here the poison bags were introduced in the wound, made in 

 the same region of the body as in the rabbit ; they were then 

 carefully opened and the contents squeezed out. In the third 

 Guinea pig four glands were thus used. The result was the 

 same as with the rabbit : the animals did not seem to be at all 

 disturbed by the operation and lived for weeks until they 

 were disposed of in the same manner as the rabbit. 



The fourth experiment was made with the mouse : the 

 poison glands the largest ones of all were here also care 

 fully opened in the wound. Result, the same as in the 

 previous cases ; the mouse seemed to enjoy particularly good 

 health after the operation. 



In the last trial another method was used for introducing 

 the virus into the system of the Guinea pig. A full-grown 

 female spider, which had been well supplied with flies and 

 beetles for a couple of days before the experiment was made, 

 was held by a pair of forceps at one of its posterior legs and 

 was thus approached to the nose of the victim, which it imme 

 diately seized and wounded. After removing the spider from 

 this place two small punctures could be distinctly noticed, as 

 a little blood oozed out, which proved that the mandibular 

 fangs had penetrated the epidermis. This operation was re 

 peated once more, with the same result. The little victim 

 was at first very much frightened and sat for awhile with 

 head bent low down, its panniculus carnosus shivering vio 

 lently. In an hour, however, it was quiet again and took 

 food. It lived for three weeks in good health, when it had to 

 follow the fate of its comrades. 



These experiments, in which Dr. Moore,. of the Bureau of 

 Animal Industry, kindly assisted, showed conclusively that 

 the poison of Lathrodectus mactans is not sufficiently strong 

 to harm a small animal. 



