560 SHEEP HUSBANDRY. 



and crude — not the result of that long and close comparison of symptoms, 

 results, and post-mortem appearances, which would give weight to the 

 opinions of the most unerudite — we have but to notice a few of the cases 

 popularly referred to the " grub in the head." A sheep in the highest 

 condition and apparent healtli leaps into the air two or three times, and 

 suddenly dies, and if a grub can be found in the cavities of the head, that 

 is the undoubted destroyer. Another wastes away for months and dies 

 lingeringly, a mere skeleton, and the same proof establishes the same fact. 

 Whether there has been fever or no fever — whether there has been obsti- 

 nate constipation, or equally obstinate dysentery — whether one viscus or 

 another exhibit traces of abnormal action — whether the disease has been 

 acute or chronic — in a word, whatever the form or character of the mal- 

 ady — however diametrically different the diagnosis and the lesions, it is a 

 clear case of " grub in the head," if two or three of those parasites are 

 found there ! 



Mr. Bracy Clark and Mr. Youatt, so far from regai'ding the larva of the 

 CEstrus ovis as the cause of a fatal disease, suggest that they may even 

 j>romote the health of the sheep by diminishing the tendency to cerebral 

 disease — especially determinations of blood — by establishing counter irri- 

 tation ! Mr. Spooner does not speak of their producing fatal effects in 

 any instances, nor am I aware that any late scientific veterinarians do. 



Treatment. — Though the presence of the grub constitutes no disease, 

 some think it well to diminish their number by all convenient means. — 

 One simple way of effecting this is by turning up with a plow a furrow of 

 earth in the sheep pasture. Into this the sheep will thrust their noses on 

 the approach of the CEstrus, and thus many of them escape its attacks. — 

 Some farmers smear the noses of their sheep with tar occasionally, during 

 the proper season — the odor of which is believed to repel the fly. Others 

 compel thfe sheep to smear their own noses every week or two, by feed- 

 ing them their salt sprinkled over tar. Blacklock says that the larvee may 

 be dislodged even from the sinuses, by blowing tobacco smoke for some 

 moments through the tail of a pipe into each nostril. I have never tried 

 the experiment. 



The Scab. — The scab is a cutaneous disease, analogous to the mange 

 in horses and the itch in men. It is caused and propagated by a minute 

 insect, the acarus. M. Walz, a German veterinarian, vvho has thrown 

 great light on the habits of these parasites, says : 



" If one or more female acari are placed on the wool of a sound sheep, they quickly ti-avet 

 to the root of it, and bury themselves in the skin, the place at which they penetrated being 

 scarcely visible, or only distinguished by a minute red point. On the tenth or twelfth day a 

 little swelling may be detected with the fintrer, and the skin changes its color, and has a 

 greenish blue tint. The pustule is now rapidly formed, and about the sixteenth day brealis, 

 and the mothers again appear, with their little ones attached to their feet, and covered by 

 a portion of the shell of the egg from which they have just escaped. These little ones im- 

 mediately set to work, and penetrate the neighboring skin, and iDuiy themselves beneath it, 

 and find their proper nourishment, and grow and propagate, until the poor animal has myri- 

 ads of them to prey on him, and it is not wonderl'ul tliat he should speedily sink. Some of 

 the male acari were placed on the sound skin of a sheep, and they too burrowed their way 

 and disappeared for a while, and the pustule in due time arose ; but the itching and the 

 scab soon disappeared without the employment of any remedy. 



The figures on the next page are copied from M. Walz's work : 

 The female acarixs brings forth from eight to fifteen young at a litter. 

 The scab is often produced spontaneously in England by mismanage- 

 ment of various kinds, such as " bad keep, starvation, hasty driving, 

 dogging, and exposure afterward to cold and wet ;" and it spreads rapidly 



(1040) 



