MICHIGAN ACADEMY OF SCIENCE. 935 



organism. It is quite probable that forms other than those which have 

 been used can be substituted to advantage, and it is to be hoped that a 

 completely satisfactory standard organism can be determined. 



SUMMARY. 



1. A method for the laboratory determination of the copper sulphate 

 coefficient of fungicides has been devised. 



2. This method has been formulated to determine the fungicidal value 

 of various fungicides in terms of a standard copper sulj^hate solution. It 

 is based upon the method of Anderson and McClintic which determines the 

 bacterial efficiency of disinfectants by comparing them with a phenol 

 solution of standard strength. 



3. The fungicides tested have been several commercial mixtures of 

 lime sulphur, ammoniacal copper carbonate and neutral copper acetate. 



4. The organisms used for the tests are Glomerella rufomaculans 

 (Berk) S & S., and Endotliia parasitica (Murrill) Anderson. 



5. The coefficients found represent the relative efficiency of the fungi- 

 cides tested as compared with copper sulphate solution at a standard 

 strength. 



This work was done at the State College of N. C. Botanical Laboratory, 

 under the direction of H. R. Fulton. 



BIBLIOGRAPHY. 



'Anderson, John F., and McClintic, Thomas B. Method of Stand- 

 ardizing Disinfectants with and without Organic Matter. Hygienic 

 Laboratory Bulletin 82, 1912. 



-Burrill, T. J. 111. Agr. Exp. Sta. Bulletin 118, 1907. 



^Butler, O. Bordeaux Mixture, Physic-chemical Studies. N. H. Agr. 

 Exp. Sta. Tech. Bui. 8, 1914. 



^Crandall, Charles S. Bordeaux Mixture. 111. Agr. Exp. Sta. Bui. 135, 

 1909. 



^"The Lancet." The Standardization of Disinfectants. London. Vol. 

 177, Nos. 4498, 4499 and 4500. 



"Rideal, S., and Walker, J. F. A. Determination of the Value of a Dis- 

 infectant in Terms of its Carbolic Coefficient. Jour. Royal Sanitary Inst. 

 London, 1903. 



