802 EXPERIMENT STATION RECOED. 



and found to contain an average of 0.0203 per cent of ether extract. By subse- 

 quently extracting 24 of the same soils with chloroform, 0.0174 per cent of 

 extract w:is obtained. The ether extract was found to be composed of 50 per 

 cent unsaponifiable and 40 per cent saponified material, with a loss of 10 per 

 cent, and probably contains fatty acids and wax alcohols. This is nearly the 

 same as the average composition of the ether extracts of plants. " The chloro- 

 form extract consists of 36 per cent unsaponifiable, 43 per cent saponified, 3 per 

 cent Insoluble, and 18 per cent loss." 



Chemical studies of the lime-sulphur lead arsenate spray mixture, W. E. 

 Ruth {Iowa Sta. Research Bui. 12, pp. 409-419). — This is a study of the reac- 

 tions which take place when lime-sulphur solution and lead arsenate are mixed. 

 It was found when bringing these 2 fungicides together that an increase in 

 the thiosulphate content of the solution and the residue and the sulphite con- 

 tent of the solution takes place. The autlior concludes that if the fungicidal 

 value of lime-sulphur wash is dependent upon its content of thiosulphate and 

 sulphites, as claimed by Haywood (B. S. R., 18, p. 853), the real function of 

 adding lead arsenate lies in the fact that it leads to the formation of these 

 substances. 



The close analogy of color formation undergone by precipitating lead thioarse- 

 nate and that of mixing lead arsenate and lime-sulphur led the author to look 

 for arsenic sulphld, but none was found. The evidence, however, seems to 

 point to the formation of a compound insoluble in lime-sulphur containing 

 arsenic and sulphur and which in all probability is lead thioarsenate. Further 

 changes noted were a decrease in both calcium and sulphur in the solution 

 and the formation of lead sulphid. 



The Harris method (E. S. R., 25, p. 414) for determining thiosulphate gave 

 good results. For previous work in this connection see other notes (E. S. R., 

 23, p. 701). 



Antiseptics and disinfectants, D. Sommekville (Jour. Roy. Soc. Arts, 61 

 (191S), Nos. S172, pp. 927-937; 3173, pp. 945-952).— A lengthy and critical expo- 

 sition of the chemical, physical, and biological principles underlying the action 

 of antiseptics and disinfectants. 



Suggested international test for disinfectants, S. Rideal ( Orig. Commun. 8. 

 Internat. Cong. Appl. Chem. [WasJiington and Neto York], 26 (1912), Sects. 

 Vla-XIb, App., pp. 261, 262). — The Hygienic Laboratory phenol coefficient 

 (H. L. P. C.) method of Anderson and McCliutic, which is based on a modifica- 

 tion of the Rideal-Walker method, is regarded as too expensive for everyday 

 control work, and a method is proposed in its stead in which are incorporated 

 the more important features of the Rideal-Walker test, as follows : 



"(1) Organism — Bacillus typhosus; (2) test culture — subcultured and filtered 

 (as recommended by Anderson and McClintic)*; (3) temperature of disinfec- 

 tion — 20° C. (as recommended by Anderson and McClintic) ; (4) dose of test 

 culture to disinfectant 0.1 cc. per 5 cc. measured from a graduated pipette 

 (as recommended by Anderson and McClintic) ; (5) calculation of results — 

 from an empirical time (yet to be fixed) with the 15 [minutes] duration of 

 the test (as recommended by Chick and Martin). 



"This test is practically the same as the H. L. C. P. method except that 

 such extensive test charts would not be required. Calculating on the basis of 

 7i minutes as the fixed time for sterility, from the H. L. P. C. test charts of 

 over 50 different disinfectant preparations examined by McQintic it was 

 found that the results agreed very closely with the reported H. L. P. C 



• Pnb, Health and Mar. Hosp. Serv. U. S., Hyg. Lab. Bui. 82, 1912, pp. 74. 



