albopida {scu(ellaris) have oviposited after being fed on meals of milk, 

 peptone sweetened with cane-sugar, or on meals of cane-sugar only. 

 It is probable that the presence of a food-odour is an important 

 factor in attracting insects ; in the case of mosquitos the odour is 

 probably that of the secretion of the sebaceous glands. Thus Daciis 

 is similarly attracted by methyl eugenol, the larva of Chrysomyia 

 {Pycnoso ma) JIaviceps hy the odour of night-soil, and the adults by the 

 spirit smell of Bassia latefolia (mohwa). 



Foster (M. H.). Preliminary Report on Carbon Tetrachloride Vapour 

 as a Debusing Agent. — U.S. Public Health Repts., Washington, 

 D.C., xxxiii, no. 43, 25th October 1918, pp. 1823-1827. 



Dry and moist heat and hydrocyanic acid gas, though effective as 

 a means of destroying body-lice on clothing, require the use of some- 

 what complicated apparatus, which is not easily transported nor 

 suitable for cleaning infested clothing in gaols, small hospitals, asylums, 

 etc. 



Investigations on the effects of carbon tetrachloride vapour as a 

 practical method of destroying lice which can be easily appHed and 

 does not injure woollen fabrics have shown it to be a most efficient 

 and convenient means of killing lice on clothing. As an insecticide 

 it appears to be very toxic, the pure vapour killing unprotected lice 

 in 15 minutes, though failing to destroy them in 10 minutes. 



The method used for delousing soldiers' clothing was as follows : — 

 Each article was fairly firmly rolled up and placed in a 10 gal. tin can, 

 19 ins. high, 12 ins. in diameter, sheathed with a light wood covering 

 and weighing 5| lb. A soiled shirt, badly infested with lice, was cut 

 into 4 pieces, each piece being tightly rolled and then wrapped in 

 10 thicknesses of ordinary sheeting. These were placed in the container 

 amongst the complete clothing of a soldier and the whole contents 

 firmly compressed so as to occupy a little more than half the total 

 space. Several layers of filter paper were laid on the top of the 

 clothing and 25 c.c. carbon tetrachloride was poured on this and the 

 top of the can was covered by several thicknesses of towelling. 

 A loose cover was placed over this to protect the can from draughts 

 while allowing the air displaced by the heavy vapour to escape. At 

 the end of two hours when the can was opened and the clothing aired 

 and examined, all the lice were found to be dead. 



The quantities of carbon tetrachloride required with 2 hours' 

 exposure are as follows : — ^For 100 cu. ins. of space, 2 c.c. ; for 231 cu. 

 in. (1 U.S. gal.) 4'5 c.c. ; for 1 cu. ft., 30'5 c.c. The tests were made 

 -at temperatures ranging from 68° to 72° F., being approximately those 

 of artificially warmed living rooms even in winter. It is essential 

 that the container should be air-tight, about twice as high as broad, 

 and only | full of clothing, as the vapour appears to be easily dissemi- 

 nated from shallow or broad receptacles. It was definitely determined 

 that the above proportions are useless against the eggs ; in one test 

 the use of 150 c.c. of the chemical per cubic foot of space prevented 

 the eggs from hatching after 8 hours' exposure, though a few of them 

 hatched after one of 4 hours. 



In considering the appUcability of carbon tetrachloride as a delous- 

 ing agent, the possible danger to human life must be borne in mind, 

 as it is slightly more poisonous to human beings than chloroform. 



(C539) a2 



