INSECTICIDE AND FUNGICIDE BOARD. 611 



A study has been completed by one of the board chemists of the 

 compositfon and properties of certain arsenates of calcium, and 

 the results have been published in the Journal of the American 

 Chemical Society, Vol. XLII, No. 2, February, 1920, under the title, 

 " The Arsenates of Calcium I. Equilibrium in the System Arsenic 

 Pontoxide, Calcium Oxide, Water at 35° (Acid Sectfon)." A sec- 

 ond paper on this subject, entitled "Equilibrium in the System 

 Arsenic Pentoxide, Calcium Oxide, Water at 35° (Basic Section)," is 

 in course of preparation and will soon be offered for publication. 



Profjress has been made in an investigation which has for its pur- 

 pose the development of an accurate method for determining the 

 total alkaloids in powdered hellebore root and ascertaining reason- 

 able standards for the same, more especially permissible limits for 

 the sand content. It is hoped that the results of this work will be 

 the subject of a future scientific paper. 



By reason of the fact that it has been claimed that dry powdered 

 calcium arsenate containing other calcium compounds suffers decom- 

 position on standing in the package, with the result that arsenic in 

 water-soluble forms is produced; a study has been inaugurated to 

 settle this point. Large samples of various manufacturers' dry 

 powdered calcium arsenate containing other compounds have been 

 purchased and stored at AVashington, D. C, and Tallulah, La., in 

 various tyjDes of containers, and samples from them are being exam- 

 ined from time to time. This investigation has not been completed, 

 but results up to the present time indicate that calcium arsenate con- 

 taining other calcium compounds does not increase in water-soluble 

 arsenic content with lapse of time. 



By reason of the fact that so many of the nicotine soaps and nico- 

 tine papers sold on the American market show a much smaller nico- 

 tine content than is claimed, a study has been started to determine 

 the rate of loss of nicotine in potash-nicotine and soda-nicotine soaps 

 and in papers im25regnated with nicotine. The study was also ex- 

 tended to include the effect of different types of containers on the 

 rate of nicotine loss, the conditions under which loss does and does not 

 occur, and the conditions which will prevent loss. Sufficient data 

 have not yet been accumulated to draw definite conclusions, but the 

 study is being continued. 



During the year an investigation was made by the microscopist 

 of the board of a microscopic method of identifying bassia in insect- 

 icides and the results have been published in the Journal of the 

 American Pharmaceutical Association, Vol. IX, No. 2, February, 

 1920. under the title "The Microscopical Identification of ^lowrah 

 Meal (Bassia) in Insecticides." 



The investigations involving; studies of many topics relative to 

 the practical use and value or the more important types of fungi- 

 cides found on the market Avere continued by the plant pathologists 

 of the board, working in cooperation with the Bureau of Plant In- 

 dustry. Considerable additional information and more conclusive 

 data of value in connection with the enforcement of the insecticide 

 act have been obtained. In the course of the year considerable in- 

 formation has been gained by the plant pathologists of the board 

 relative to the compatibility of various fungicides and insecticides 

 when used as combined sprays, both from the standpoint of the effect 

 of such combinations on the fungicidal properties and of their in- 



