200 



HARDWICKE'S SCIENCE-GOSSIP. 



"Popular Science Monthly" (New York) of May 

 last is an account of a curious case by Bernard 

 Bienenfeld of San Francisco. A clog was bitten on 

 the nose by a rattlesnake. The dog suffered for a 

 few days, but did not die. He became transformed 

 from a sprightly and intelligent animal to a sickly 

 and stupid one. He was emaciated and miserable, 

 and his vision was greatly impaired ; "in fact, all 

 his faculties seemed to be benumbed." Some time 

 after, this dog was taken to the banks of the Upper 

 Sacramento River in the autumn, when they are 

 lined with the decaying bodies of "dog salmon," 

 i.e. salmon that have died from exhaustion while 

 endeavouring to ascend the river for spawning. The 

 bitten dog and other " canine camp-followers partook 

 voraciously of this free salmon-feast, with the result 

 that all of them, with one single exception, died, 

 with every indication of being poisoned. The single 

 exception was the young dog that had suffered from 

 the rattlesnake bite. He apparently suffered no 

 discomfort from his meal ; and, strangest of all, from 

 that time became a well dog ! He regained his 

 youthful elasticity of spirit and became robust." 

 Mr. Bienenfeld adds that "when I last saw him he 

 was as playful and intelligent a dog as I have ever 

 seen." The question suggested is, whether there is 

 developed in salmon, and possibly in other decaying 

 fish, a counter-poison to that of the rattlesnake, and 

 Mr. Bienenfeld asks for further investigation of the 

 subject in this direction. I think he is well justified 

 in doing so. Vaccination and other forms of innocu- 

 lation operate on the principle of killing one form of 

 disease-poison by the presence of another, and there- 

 fore the hypothesis that poison of the putrid salmon 

 poisoned the poison of the rattlesnake is not un- 

 reasonable. 



CHAPTERS ON ANIMAL PARASITES. 



By W. A. Hysloi 1 . 



No. V. 



WE now enter upon the second division of the 

 Mallophaga, viz. those having the antenna; 

 clavate. 



1. Colpocephalum. — This and the next genus, the 

 Menopon, are perhaps the two most difficult to dis- 

 tinguish, and are, at the same time, the only two 

 genera of this second division of the Mallophaga 

 which are anything like common. In a short article 

 like the present it would be impossible to enter upon 

 the minute differences between them ; but a reference 

 to Figs. 123 and 124, which are typical examples, will 

 show the chief differences. 



2. Nitzschia. — There are only two species of this 

 genus, both of which are found on the swift, and 

 bear a strong resemblance to a Menopon, only they 

 are larger and more robust. 



3. Lremobothrium contains but few species, all of 

 which are of large size and rare. The largest of all 

 the known Anoplura, L. titan, belongs to this genus. 

 The structure of the head (see Fig. 125) is an unfailing 

 guide in distinguishing the genus. 



4. Trinoton. — This, though commoner than the 

 last genus, is also rare. The species somewhat 

 resemble the Menopon, but are generally of larger 

 size, and the legs thicker and shorter. The most 

 common is that found on the goose, though this is 

 not the common goose parasite. 



5. Physostomum. — This genus contains a few para- 



**$c^f* 



Fig. 123. — Colpocephalum of 

 Rook. X 60. 



Fig. 124. — Menopon of Piliatei 

 Jay, 9- X 60. 



. J ■■ 



Fig. 125. — Head and part of thorax of 

 Laemobothrium of Kite. 



Fig. 126. — Trinoton of 

 Swan. 



sites, all of which are rare, and seem to be confined 

 to song-birds. The structure of the head (see Fig. 127) 

 is again the distinguishing feature. The species are 

 tolerably large in size, and never found in large 

 numbers, that infesting the chaffinch being one of the 

 most common, though a great number of chaffinches 

 may be examined before a single specimen is found. 



6. Eureum. — This is the "rarest of all the Anoplura, 

 and contains only two species, one found on the 

 swallow, and the other on the swift. The British 

 Museum contains one specimen, and probably it is 

 the only one in any collection in Britain. Fig. 128, 

 taken from M. Piaget's book, shows the appearance 



