105 



a tax was levied throughout the district, and this enabled drainage 

 operations to be carried out over about 3,000 acres. At the end of the 

 first fiscal year, rather less than £1,000 had been spent in ditching and 

 drainage, while mosquitos have practically disappeared from the region. 



Morris (H.). Some Carriers of Anthrax Infection. — Jl. Amer. Vet. 

 Med. Assoc, Washington, B.C., Ivi, no. 6, March 1920, pp.G06-608. 



Much of the matter in this paper is quoted from one previously 

 abstracted [R A.E., B, vi, 181]. Experiments with the horn-fly [Ltf- 

 perosia], the green-headed horse-fly [Tabamis sp.] and the swamp 

 mosquito [Aedes sylvestris] have shown that blood-sucking insects after 

 feeding on the blood of an anthrax-infected animal are capable of 

 transmitting the disease to healthy ones. The transmission seems 

 to be mechanical, the infection being carried upon the proboscis of 

 the insects. Non-biting flies too may be carriers. House-flies [^Musca 

 domestical and blow^-fhes carry infection from anthrax-infected flesh 

 by walking over a fresh surface wound in a healthy animal. Blow- 

 flies bred from an unopened anthrax carcass did not carry infection 

 in or on their bodies. This seems to be due to the destruction of anthrax 

 bacilli in the carcass by the process of putrefaction. When however 

 they were bred in the presence of anthrax spores, they carried infection 

 both externally and internally. This proves the importance of keeping 

 the natural openings of the carcass closed and the skin free from lesions, 

 as anthrax spores do not form in the unopened carcass ; once the 

 spores are allowed to form, the process of decomposition has no effect 

 on them. 



The Argentine ant [J ridomijrmex humilis] leaves a trail of infection 

 after feeding on an anthrax carcass. 



Parker (R. R.). The present Status of the Control of Dermacentor 

 venusttis, Banks, in the Bitter Root Valley, Mont., and the New 

 Data concerning the Habits of the Tick. — Jl. Econ. Entom., 

 Concord, N.H. xiii, no 1, February 1920, pp. 31-37. 



The control of the wood-tick, Dermacentor venustus, the chief trans- 

 mitting agent of Rocky Mountain spotted fever is a difficult problem, 

 although very considerable progress has been made in areas where work 

 has been conducted. Two questions present themselves. One concerns 

 the permanency of the results obtained, the other the possibihty of 

 finding some simpler and quicker method of operation. Lack of 

 knowledge of the real source of the disease among wild mammals is a 

 great handicap. If, for example, certain rodents were involved, measures 

 directed against them would be much more certain of rapid and 

 permanent results than those directed against the tick. 



Under the present methods of tick control, viz : — ^rodent destruction ; 

 the restriction of grazing ; dipping and hand-picking of stock ; quaran- 

 tine and cultivation — complete eradication will take five years or more, 

 depending on the thoroughiiess with which the work is carried out. 

 These measures must vary with local conditions, wliicli differ from each 

 other to a very great extent, and the difficulty of adapting the system of 

 control to them is great. A method that would be of more general 

 apphcation is very desirable. Such a plan may be evolved by a study 



