79 the previous formula and the resulting preparation when cold formed a thick dark brown pasty mass. It was therefore heated up and diluted with three parts of water, when it formed a dark brown treacle-like liquid smelling strongly of carbolic acid. When a little of this solution was added to water it formed a dirty white emulsion. 202. On being tested as a larvacide it was found to be very active, destroying mosquito larvæ readily, even when used in very great dilution. The original solution was made up so as to contain 25 per cent. of the crude carbolic acid. Dilutions of this solution acted upon the larvæ of mosquitoes in the following manner :- Anopheles larvæ. Bulex larvæ. Stegomyia larvæ. Emulsion 1-1,000 ( = to 1-4,000 of original carbolic acid). All died in 6 minutes. All died in 8 minutes. All died in 8 minutes. Emulsion 1-5,000 (=to 1-20,000 of original carbolic acid). All died in 15 minutes. All died in 20 minutes. All died in 20 minutes. Emulsion 1-10,000 ( = to 1-40,000 of original carbolic acid). All died in 5 hours. Almost no action. Almost no action. 203. These results compare favourably those given in the following table :- Larvacidal action of disinfectants. Anopheles larvæ. Culex larvæ. Stegomyia larvæ. McDougall's Saponified Cresols. 1-1,000 All died in 7 minutes. All died in 8 minutes. All died in 8 minutes. Do 1-5,000. All died in 15 minutes. All died in 20 minutes. All died in 20 minutes. Phenyle1-1,000. All died in 12 minutes. All died in 15 minutes. All died in 15 minutes. Do.1-5,000. All died in 1/2 hour. All died in 3/4 hour. All died in 3/4 hour. Jey's Fluid 1-1,000. All died in 12 minutes. All died in 20 minutes. All died in 20 minutes. Do.1-5,000. All died in 25 minutes. All died in 28 minutes. All died in 1/2 hour. Izal. 1-500. All died in 6 minutes. All died in 5 minutes. All died in 5 minutes. Do.1-1,000. All died in 9 minutes. All died in 9 minutes. All died in 9 minutes. Do.1-5,000. Almost no action. : All died in 4 to 8 hours. All died in 4 to 8 hours. 204. As crude carbolic acid can be obtained in bulk at a price of about one rupee a gallon or less, an exceedingly cheap and efficient larvacide can be prepared from it. In use it is found to have more action upon larvæ than pupæ, and nearly mature larvæ pupate rapidly on coming into contact with it, so that it is a good plan to combine its use with that of kerosene or pesterine. The original solution mixes with either kerosene or pesterine and very greatly improves their toxic action and their powers of spreading quickly and evenly. This is shown by the following experiments:-