FUNGICIDES 649 



Among the insecticides that are used for this purpose are kero- 

 sene emulsions, potash fertilizers, strong soap, or tobacco washes, 

 tobacco dust, carbon disulfid, etc. Methods for examining these 

 materials, except carbon disulfid, have been given in the pre- 

 vious parts of this article. The potash fertilizers are examined 

 for potash by the usual fertilizer methods. 



545. Insecticides for Insects Affecting Stored Grains and Other 

 Stored Products. While there are a number of important reme- 

 dial measures against insects in stored products, such as agita- 

 tion of the grain, heating, etc., the only important insecticide 

 that is necessary to consider in this connection, is carbon disul- 

 fid. As has previously been mentioned, special chemical meth- 

 ods for testing the purity of this compound have not been 

 proposed. 



546. Insecticides for Animal Parasites. Among the most im- 

 portant insecticides of this class are tobacco extracts, lime-sulfur 

 mixtures and creosote dips. There are of course other remedies, 

 but not any that the chemist will be called upon to examine with 

 anything like the frequency that he is called on to examine the 

 three classes of insecticides mentioned above. Methods for ex- 

 amining tobacco extracts and lime-sulfur mixtures have already 

 been given. For examining creosote dips, the method given by 

 Allen is usually followed. This method is far from perfect and 

 gives only approximate results. 81 



547. Fungicides. Among substances that are used as fungi- 

 cides, or as ingredients in making insecticides, the chem- 

 ist is most often called upon to examine the following: 

 Bordeaux mixture, copper sulfate, copper carbonate, lime-fer- 

 rous sulfate, sulfur and formaldehyde solutions. Methods for 

 examining the first six of these are based on general principles 

 and are so self-evident that it does not seem necessary to mention 

 them. It may be said, however, in passing, that the Association 

 of Official Agricultural Chemists has adopted official methods 

 for determining copper in copper carbonate. 32 



81 Allen, Commercial Organic Analysis, 3rd Edition, 1907, 2, Part 2 : 262. 



Bureau of Chemistry, Bulletin 90, 1905 : 103. 

 3J Bureau of Chemistry, Bulletin 107, 1907 : 30. 



