103 



Mercuric chloride was dissolved iu water auu the concentrated solu- 

 tion colored with "aniline rose i)ink, 3 B." This solution and one 

 containing common salt and holding more of the mercuric chloride but 

 colored as deeply as the first, were used as preservatives. Samples of 

 milk to which these were added were kept in the laboratory from seven 

 to thirty-three days at a temperature varying from 55'^ to 75° Fah. 

 The percentages of fat were determined at the beginning and end of 

 each trial. Fourteen trials were made with the first and eleven with 

 the second solution. The results, given in detail, imply that 10 to 15 

 grains of mercuric chloride are sufficient to preserve 200 to 400 cubic 

 centimeters (one fifth to two fifths of a qnart) of milk in a warm room 

 in winter so that the determination of fat by the autlior's method is not 

 interfered with. A serious objection to the use of the corrosive sub- 

 limate is that it is a violent poison. For this reason the author does not 

 care to recommend its general nse in creameries, and hopes that in the 

 future some harmless preservative will be found. A plan for the prac- 

 ticable application of the author's method is given in detail. It is now 

 being used in a creamery at Brandon, Iowa. 



Table of relatire values. — To facilitate the adoption of the relative 

 value plan a table is given which may be used iu calculating the prices 

 of milk per 100 pounds, with directions for the use of the table. This 

 table is similar to that published in Bulletin 'No. 16 of the Vermont Sta- 

 tion. 



Plum curculio and plum gouger, 0. P. Gillette, M. S. (pp, 

 370-388). 



Plum curculio {Conotrachclus nenuphar). — Observations by the author 

 in 1889 with reference to the breeding of this insect in Iowa are re- 

 ported. The results agree with those of other observers in showing 

 that "the curculio is not double brooded iu Iowa, but the eggs deposited 

 late in July and August are from belated females." A tabulated record 

 is given of the fruit injured by the curculio on trees of four imported 

 aud seven native varieties of plums. The per cent of fruits injured iu 

 the case of the imported varieties varied from 14 to 66 and averaged 

 4G.8 ; for the native varieties it varied from 2.5 to 25.8 and averaged 

 6,G. Analyses of specimens of five varieties of plums, made by the 

 station chemist, are recorded, which show percentages of water varying 

 from 75.3 to 85.5. In connection with the observations on the curculio, 

 these analyses indicate that "the succulent, quick-growing plums are 

 not less attacked than slow-growing varieties." 



Observations of the action of the curculio on the Duchess apple are 

 also reported, and the curculio parasite {Sigalplius curculionis) is illus- 

 trated and briefly described. 



Eecords of two applications of London purple (May 4 and 11) indicate 

 that " although not made at the times best suited to destroy the cur- 

 culio, they apparently gave a protection of 44 per cent against the 

 ravages of this insect," 



