94 



during the summer one of these "vvill be used for one week and then 

 dammed up while the water is allowed to flow into the other. The 

 channel not in use will dry up during the week, so that these outlets- 

 may be regarded as mosquito traps. By applying this principle to 

 irrigation, breeding places may be rendered harmless without prejudice 

 to agricultural requirements. 



Canalis (P.). Some experiments on the insecticidal action of Clayton- 

 gas. — Bull. Mens. Office Internal. d'Hyg. Publique, Paris, viii, 

 no. 3, March 1916, pp. 457-463. 

 This paper describes experiments with Clayton gas against fleas^ 

 bugs and cockroaches. These were made in a large room of the Genoa 

 maritime sanitary station and in the holds of five vessels in the harbour. 

 It was found that in all cases the gas at 2 or 3i per cent, strength killed 

 the innumerable cockroaches and fleas as well as the bugs and their 

 eggs. The time required to reach the above strength varied Avith the. 

 size of the spaces dealt with, in the case of those of from 80 to 750 

 cubic metres, four hours w^ere sufiicient. The gas is always more 

 concentrated in the lower strata, so that when the upper spaces contairt 

 a strength of 2 per cent., the destruction of the insects may be con- 

 sidered certain. Detailed tables are given in the case of eacli 

 experiment. 



Egberts (N.) & Robertson (G. E.). Fumigation of the U.S.S. Ten- 

 nessee by the Cyanid Method. — U. S. Naval Med. Bull., 

 Washington, B.C., x, no. 2, April 1916, p. 296. 



The methods by which the U.S.S. Tennessee was fumigated at the 

 Navy Yard, Philadelphia, Pa., in September 1915, to rid her of rats^ 

 coclioaches and bed-bugs, is described. The material required was 

 750 lb. of sodium cyanide (in egg-shaped lumps weighing 1 oz. each), 

 1,000 lb. of sulphuric acid, 400 three-gallon (U.S. gallon) cedar buckets,. 

 25 lb. of paraffin, 50 lb, of washing soda, 400 two-pound paper bags^ 

 about 800 labels, and two large barrels. Every compartment in the 

 ship was tabulated and the cubic space estimated, except the double- 

 bottoms and the magazines, which were considered to be uninf ested as 

 they were habitually closed off from the ship proper. One bucket 

 was allowed to every 3,000 cubic feet. The planning of the route to 

 be foUowed by the operators was the most difficult part of the fumi- 

 gation, insomuch as the party had to go into every part of the ship,, 

 start the generators, escape and shut the entrance behind them without 

 at any time passing through any space already containing gas. The 

 cedar buckets were paraffined to prevent their destruction by the acid. 

 They were filled from the barrels in which the acid and water were 

 mixed. About two or three quarts of the diluted acid was used per 

 bucket. Each bucket was labelled to show the amoimt of acid it 

 contained and its destination. The paper bags were simultaneously 

 fiUed with cyanide, labelled and distributed. By dropping the bags 

 into the buckets (instead of emptying their contents) additional safety 

 was ensured by the shght delay in the generation of the gas. The 

 ship was kept closed for fourteen hours and the crew were not allowed 

 on board until eighteen hours after the ship was opened. Three months- 

 after fumigation the ship was still free from rats, there were only a few 

 cockroaches and, it is believed, no bed-bugs. 



