oct. — dec. 1857] Notices of Boohs. 



151 



it out a little way, and it assumes a crimson colour as the man- 

 dibles come into brisk operation. The previously shrunken belly 

 swells out, and if left undisturbed the fly quietly departs when it is 

 full. A slight itching irritation follows, but not more than in the 

 bite of a mosquito. In the ox, this same bite produces no more 

 immediate effects than in man. It does not startle him as the gad- 

 fly does ; but a few days afterwards the following symptoms su- 

 pervene : the eye and nose begin to run, the coat stares as if the , 

 animal were cold, a swelling appears under the jaw, and sometimes 

 at the navel; and, though the animal continues to graze, emaciation 

 commences, accompanied with a peculiar flaccidity of the muscles, 

 and this proceeds unchecked until, perhaps months afterwards, 

 purging comes on, and the animal, no longer able to graze, perishes 

 in a state of extreme exhaustion. Those which are in good con- 

 dition often perish soon after the bite is inflicted with staggering 

 and blindness, as if the brain were affected by it. Sudden changes 

 of temperature produced by falls of rain seem to hasten the pro- 

 gress of the complaint ; but in general the emaciation goes on un- 

 interruptedly for months, and do what we will, the poor animals 

 perish miserably. When opened, the cellular tissue on the surface 

 of the body beneath the skin is seen to be injected with air, as if a 

 quantity of soap bubbles were scattered over it, or a dishonest awk- 

 ward butcher had been trying to make it look fat. The fat is of a 

 greenish-yellow colour and of an oily consistence. All the muscles 

 are flabby, and the heart often so soft that the fingers may be made 

 to meet through it. The lungs and liver partake of the disease. 

 The stomach and bowels are pale and empty, and the gall-bladder 

 is distended with bile. The symptoms seem to indicate what is 

 probably the case, a poison in the blood ; the germ of which enters 

 when the proboscis is inserted to draw blood. The poison-germ, 

 contained in a bulb at the root of the proboscis, seems capable, 

 although very minute in quantity, of reproducing itself, for the 

 blood after death by tsetse is very small in quantity, and scarcely 

 stains the hands in dissection. I shall have by and by to mention 

 another insect, which by the same operation produces in the hu- 

 man subject both vomiting and purging. The mule, ass, and goat 

 enjoy the same immunity from the tsetse as man and the game." 



