The Pamphlet Collection of Sir Robert Stout: Volume 29
To the Editor of the New Zealand Country Journal
To the Editor of the New Zealand Country Journal.
Sir,—In the month of October last, I observed in the Canterbury Times a copy of a paper read at a meeting of the Kaiapoi Fanners' Club, by Mr. P. Duncan, on the œstrus Ovis of New Zealand. Soon after that, while taking my sheep home to be shorn, I found one of the hoggets unable to get up on its hind-quarters; thinking it had been hurt by some of the other sheep, I brought it in to the homestead on a dray, and as it appeared in good health and eat grass, I left it about the place for several days. One morning I found it had lost the use of one fore-foot at the pastern joint, and next day it had lost the use of the leg altogether. I then killed it, and examined the head very minutely, having divided it in two with a saw. At the top of the left nostril, and rather behind and above the eye close to the brain, I found six very small larvæ—all alive. Further up, and in the small folds or leaves in the nostril, only a thin membrane dividing them from the brain, I found two page 178 large ones—one as large as a common maggot, and in size and shape very much like those blown by the large blow-fly. There was only the thin membrane between them and the brain, and still the brain was clear and healthy looking, and without any appearance of inflammation, and I could detect nothing about either the brain or spine which could cause the disease the sheep suffered from. On opening the right nostril I found appearances of inflammation, and a number of small larvæ, which had evidently been deposited longer than those found in the other nostril. I also found three large worms in a similar position to that in which I found three large ones in the left nostril, two of which had evidently been deposited long before the others. You will know them in the glass sent herewith; they are finely striped brown and white across the back, with the head and tail brown. Two of the others were all white, except the head and tail, which were brown. In all, I found 15 larva;, which I put into strong spirits of wine as soon as I removed them from the head. The small ones died almost immediately, but the large ones showed signs of life for at least six hours after they had been put into the spirits. From what Mr. Duncan said in his paper I was afraid we should have a plague among the sheep in this Province; but unless the sheep above mentioned was affected by the larvæ found in its head, I have seen no bad effect from the œstrus Ovis. In killing fat sheep for home use, I have frequently found worms in the head; but I have never noticed anything about the sheep which would lead me to believe that they were affected by them.
I send you some specimens of the fly which deposits the worms. You will observe there are two different kinds—one brown, and the other a small blue fly, both of which blow the worms above.
W. Morrison.Maitland Vale, Cust.
[The specimens sent by Mr. Morrison have been handed to Dr. Powell.—Ed.]