210 



the common occurrence of worm nodules in the stomach have led to 

 the observation of a causal connection between flies and these 

 neoplasms. A form of tetanic immobility of the membrana nictitan& 

 arising apparently from constant irritation by flies has been noted 

 in the season when flies were abundant. The ducts of the lachrymal 

 gland are such that they are easily penetrated or perforated by the 

 proboscis of Miisca domestica or Stomoxys calcitrans. The custom 

 in South Australia of bedding horses upon dung leads to the rapid 

 multiplication of these flies, as well as of Muscina stahulans. The eggs 

 are laid in the dung of the horse, kangaroo, wallaby or rabbit. In 

 the course of autopsies on 150 horses, about 91 per cent, showed 

 nematode tumours in the stomach and nearly 50 per cent, exhibited 

 growth upon the membrana nictitans or suft'ered from opacity of the 

 cornea. In India, intra-ocular filariasis is due to the presence of 

 Filaria papillosa, but in Australia no adult worms have been discovered 

 in the anterior chamber of the eye. Nematode parasites have been 

 found in the head of Stomoxys calcitrans and Musca domestica and have 

 been observed to survive for 2 days after the death of the fly. Horses, 

 must therefore ingest the larvae surviving in the moisture of the chaff 

 and these are ultimately found in the submucosa of the stomach. 

 Larval worms are doubtless vomited in large numbers upon the chaff 

 by flies, and fly pupae have been found in the stomach of the horse, and 

 these may constitute a source of infection. 



Continuous application of ice and silver salts, such as the nitrate, 

 appear to destroy the irritant nematodes. The control of the 

 distributing agents, namely, flies, is by far the more important 

 measure. Frequent disturbance of the dung is useful, but 

 periodical spraying of dung with poisonous compounds is too dangerous 

 to be practicable. A dry stable floor will retard the development of 

 the larvae. Traps of wire gauze set in convenient openings will 

 materially reduce the numbers of adults. Bunches of eucalyptus 

 leaves, hung from the roof of the stable, attract flies towards evening 

 and large numbers can be caught by slipping bags over the leaves. 



Strength of the Dipping Tank. — Rhodesia Agric. Jl., Salishury, xii, no. 4, 

 August 1915, pp. 441-446. 

 Eecent outbreaks of African Coast fever in Mashonaland have 

 shown that in some cases the fluid in dipping tanks was not up to the 

 required strength. It is advisable to maintain the fluid in the tank 

 always at a certain level. Each animal passing through the tank 

 removes approximately half a gallon of fluid and this must be replaced. 

 If, previous to dipping, the level is found to have dropped, the loss 

 is due to evaporation and water only must be added. The dipping 

 fluid is liable to undergo chemical change and should be submitted 

 to laboratory test from time to time. A fluid of correct strength is 

 obtained by allowing 1 gal. of Cooper's Improved Cattle Dip to 

 200 gals, water. Experiments carried out at Salisbury to determine 

 whether oxidation of arsenical dipping fluids can be prevented by the 

 application of disinfectants gave unsatisfactory results. In connection 

 with the apparent loss of arsenic by oxidation, it does not appear 

 necessary to renew a dip in which a fair number of cattle are dipped 

 at short intervals, until it has become too dirty for use. 



