184 



experiments that an intermittent low temperature does interfere with 

 sporozoite formation ; consequently it is explicable that mosquitos 

 procuring gametocyte-bearing blood before winter sets in may become 

 sterile or innocuous during the hibernation period. 



The author has obtained a partial confirmation of the results of Daniels 

 in the relation of infection to the number of bites which the mosquitos 

 obtain. Fifteen examples of A. puncti^oennis gave the following results 

 relative to infection with the parasites of malaria : One, two and three 

 bites gave 12-5, 18'8 and 34"8 per cent, respectively. The results 

 obtained wath four specimens of A. quadnmaculatus were 20, 50 and 100 

 per cent, relative to one, two and three bites obtained. Another factor 

 besides low temperature which possibly influences infectivity was 

 found to be the loss of gametocytes through the " clearing process " 

 in the mosquito. This is indicated in the blood count of the mosquitos' 

 dejecta, in which numerous crescents w^ere found. In one instance 

 blood from the human host yielded 63 crescents to 100 leucocytes, and 

 in the blood after passing through the mosquito 87 crescents to 100 

 leucocytes were counted. 



In a recent paper King (1917), working in New Orleans, has shown 

 some interesting results relative to low temperature influence on the 

 sporogonic development [see this Review, Ser. B, v, p. 73]. He shows 

 that the parasite of tertian malaria in Anopheles quadrimaculatns is 

 able to survive exposure to a temperature of 30° F. for a period of 

 2 days. 31° F. for 4 days, 45° to 69° F. for 6 to 7 days, and in two 

 mosquitos 38° to 59° F. for 17 days. In a smaller series of tests the 

 sporonts of P. falciparum showed a resistance to 35°-57° F. for 

 1 to 2 days. In these experiments the parasites in the mosquito were 

 permitted to develop during 7 to 23 days at room temperature before 

 the insects were exposed to temperature of 29° to 69° F. for periods 

 ranging from 1 to 16 days, following which they were maintained at 

 room temperature for an additional period of 1 to 19 days. It is 

 indicated from these tests that exposure to low temperatures, for a 

 limited period at least, did not affect the viability of sporozoites, 

 assuming that provision had been made for the mosquitos to develop 

 sporozoites at room temperature. 



Barber (L. B.). Report of the Veterinarian and Animal Husband- 

 man. — Bept. Guam Agric. Expt. Sta., 1916, Washington, D.C., 

 3rd August 1917, pp. 41-58. [Received 5th October 1917.] 



Until 1916, hand-picking and treatment with oil and kerosene were 

 used in the attempt to keep down tick infestation on imported pure- 

 bred Ayrshire cattle, but neither method kept them even reasonably 

 free from ticks, two of the five imported animals dying of tick fever. 



An arsenical dip made according to the formula used in the southern 

 United States has been employed since July 1915 with very good 

 results, the cattle, with one exception, having been free from ticks 

 during that time. 



Among the parasites of domestic animals causing disease during the 

 year, were : Margaropus caudatus (common cattle tick), Haematopinns 

 tuberculatus (carabao louse), H. suis (hog louse), Trichodectes climax 

 (goat louse), Goniocotes gigas (large chicken louse), Menopon pallidum 

 {trigonocephalum) (common chicken louse) and Dermanyssus gaUinae 

 (red chicken mite). 



