105 



disinfectant into 50 gallons of water, stir thoroughly and apply to 

 pools and gutters with a sprinkler. Sewer eateh basins were not 

 treated because it was not realized until late in the season how many 

 of the insects bred in such places. 



"PURALIXE." 



This is a preparation similar to the preceding, but much cheaper, 

 and is also used as a disinfectant. It dissolves in water in the same 

 way and produces a milky mixture. Cresol is the active base. 



Several mixtures more dilute than 1 to 10,000 were tried, and 

 proved practically ineffective. Larva? and pupae of Chdex pungens 

 only were used. The effective mixtures were as follow-: 



To jar Xo. 1 I added from the stock solution enough to make the 

 proportion 1 to 8.000. An hour afterwards a few larvae and all pupae 

 were yet alive, but next morning everything was dead. 



Jar No. 2 received stock solution to make the mixture 1 to 4r,000 3 

 and an hour afterwards all larvae and nearly all pupae were dead. 



At 1 to 4.000 this material is as effective against mosquitos as the 

 chloro-napthalum is at 1 to 1,000 — that is. four times as effective at 

 one-fourth the price. Its range of usefulness is as for the previous 

 mixture. 



; * TAROLA." 



This preparation is from the Barrett Manufacturing Company: is 

 also soluble in water, and produces a milky emulsion. 



The usual 1 to 100 stock was made, and 5 cc was added to 500 cc of 

 water containing larvae and pupae of CuLex and Anopheles, at 10.40 

 a. m. An hour later most of the Gvlex larvae were dead. At 3.15 

 p. m. a few more pupae were dead. Next day at s a. m. no more pupae 

 had died, and I added 10 cc from the stork, making the mixture 1 to 

 2,500; but at 11 a. m. many pupae were yet alive. 



The remarkable resistance of the pupa 1 to preparations of this char- 

 acter is quite noticeable, and at 1 to 2,500 it was not really more 

 effective than at 1 to 5,000. 



"milky disinfectant." 



This is another of the preparations of the Barrett Manufacturing 

 Company, and produces the same milky emulsion. 



The usual 1 to loo stock was prepared, and at 8 a. m. 5cc was added 

 to 500 cc of water containing Larvae and pupae of Anopheles sad Qui . 

 An hour later all the larvae were dead. At 10.30, as no pupae were 

 dying, I added :» cc from \\w stock solution. At 3. L5 p. m.. no change 

 being noted. 1 added 5 cc additional from the stock, and at 5.45 p. m. 

 a few pupa 1 were dead. At S a. m. of the day following some pupae 



