LOCOWEED DISEASE OF SHEEP 407 



the}' raise clouds of dust to deceive their enemy. It is during rumination that the 

 insect finds a particularly favorable time for depositing its progeny. Its small size, 

 gray color, and the rapidity of its flight, do not allow its ovulation to be observed; but 

 there can be no doubt that it does not take place on the nose of the sheep. As soon, 

 in fact, as these animals have been touched by the Oestrus, they become excited, 

 run in every direction, hold down their noses and rub them against the ground or 

 against their feet; often look anxiously around them, sneeze and snort, and seek 

 ditches, furrows and dusty roads. Owing to the repeated rubbings, the nostrils are 



often abraided and inflamed Symptoms. — It is usual to find three or 



four larvae of the Oestrus in the frontal sinuses of sheep, which, during life, had not 

 given any indication of their presence. They rarely occasion any morbid disturbance, 

 unless they are numerous and advanced in development at the commencement of 

 spring. The first sign of their presence is a discharge, often unilateral, at first clear 

 and serous, then thick and mucus, from the nostrils. Then there are frequent sneez- 

 ings and snortings, accompanied by the expulsion of the mucus, and sometimes of 

 the larvae. Later the animals throw the head upwards, often shake it, rub the nose 

 on the ground, against some part of the body within reach, or with the forefeet. As 

 the malady progresses the sheep hold their heads low, lift their limbs high in move- 

 ment, as if walking in water — their gait resembling that of horses affected with im- 

 mobilitie. Sometimes they suddenly throw up the head, carry the nose high, then 

 move it convulsively. From time to time they stagger and are attacked with vertigo, 

 but they do not turn in a circle. In more serious cases there is dyspnoea, the upper 

 air-passage being obstructed by the larvae or the inflammation of the pituitary mem- 

 brane. The eyes are red and lachrymose. The disease may be more complicated, 

 the animals losing their appetite and their condition; they grind their teeth; foamy 

 saliva flows from their mouth; the eyes pirouette in their orbits; and convulsions set 

 in, then death ensues, sometimes in six to eight days after the appearance of the 

 first symptoms The common saying that a whimsical person is 'mag- 

 goty, ' or has got 'maggots in the head, ' perhaps arose from the freaks of sheep affected 

 by these larvae. 



"But it is rare that the malady reaches this paroxysm; it continues for a long time, 

 and generally — the larvae being ejected one after another — the symptoms gradually 

 subside, until they disappear altogether." 



On September 6 the experiment was closed having lasted fifty-three 

 days. The animals at that time had eaten bare a wide patch of loco. The 

 total area covered by the sheep feeding on loco was: Groups IV and V, 

 57,894 square feet; Group VI, 289,854 square feet; Groups VII and VIII, 

 387,084 square feet. The corrals varied from 16,000 to 48,000 square feet 

 in size. 



The animals did not thrive on Ten Mile Flat, and did not do nearly so 

 well as the original band (3,200), from which the animals were selected for 

 experiment and which were kept on the mountain side where the forage 

 was fairl}' abundant, and living conditions better. Even in this band, how- 

 ever, there were one or two hundred animals undersized, stiff-legged and 

 evidently suffering from sheep fly disease. 



