136 



a window at a temperature of 65° to 67° F. In twenty-four hours 

 all the larvae in the treated water were dead, while those in the control 

 all developed normally. The experiment was repeated with 90 small 

 and 10 large larvae in each trough, only half a gramme of naphthalene 

 being used. In twenty-seven hours all were dead in the test trough 

 and all ahve in the control ; the room temperature in this case was 

 lower, viz., 60° F. A third experiment with only 0'2 gramme of 

 naphthalene was tried, all the small larvae were dead after 72 hours 

 and only 10-12 per cent, of the larger ones survived ; all the naphtha- 

 lene had evaporated. The author did not have an opportunity of 

 repeating the observations with naphthalene suspended above the 

 surface of the water. 



HoLBOROw (A. G.). Oxidation of Arsenical Dipping Fluids. — Rhodesia 

 Agric. JL, Salisbury, xi, no, 4, April 1914, pp. 579-581. 



The apparent loss of arsenic in dipping-tanks, due to micro-organisms 

 which cause a change, by oxidation, of sodium arsenite into sodium 

 arsenate is here dea't with. The essential quality of a cattle 

 dip is the presence of a correct proportion of sodium arsenite, 

 the arsenate having less than half as much poisonous effect on ticks. 

 When dips are in constant use the change is only partial, but when 

 undisturbed and in Vv'arm weather, it may be complete. Investigations 

 under local conditions were made, Cooper's dip being used at a strength 

 of 1 gallon in 300 gallons of water, more dip being added to replace that 

 taken out by cattle and to correct flood water. The arsenite and 

 arsenate contents were determined at frequent intervals, the longest 

 period during which the dips were at rest being four days. The 

 results showed that oxidation was neither constant nor regular, and it 

 is concluded that where cattle are constantly dipped at short intervals, 

 there is no need to change the dip until it becomes too dirty for use. 



Sinclair (J. M.). Arsenical Poisoning. — Rhodesia Agric. Jl., Salisbury, 

 xi, no. 4, April 1914, p. 614. 



The mortahty amongst domestic animals from arsenical poisoning 

 is increasing at an alarming rate, and the attention of stockowners 

 is directed to the necessity of keeping cattle-dip and other preparations 

 containing arsenic under lock and key. The greatest carelessness is 

 frequently displayed in leaving such preparations so that they are 

 readily accessible to animals. In two cases recently investigated by 

 the Department of Agriculture, over forty head of cattle died through 

 tins of pure dip being left on the veld. 



Morrill (A. W.). Some American Insects and Arachnids concerned 

 in the Transmission of Disease.— ^.4rzzona Med. JL, Phoenix, Jan. 

 1914. Reprint 12 pp., 8 figs. [Received 17th Aug. 1914.] 



After briefly outhning the habits and hfe-history of the North 

 American cattle tick, Boophihs annulatus, the author says that 



