BUREAU OF ANIMAL INDUSTEY, 125 



been continued, and a number of bacteriological examinations of 

 samples of meat and canned goods have been made from time to time 

 for the Meat Inspection Division to determine the possible presence 

 of bacteria Avhich might be harmful to human health. 



The preparation of branding ink for marking inspected meats has 

 been continued, 2,475 gallons of this ink having been prepared during 

 the year at a cost of $1,127.25 for materials and containers. 



DIPS AND DISINFECTANTS. 



The laboratory of dips and disinfectants has received during the 

 year 395 samples for examination. These consisted of samples of 

 arsenical dips, nicotin solutions, lime-sulphur solutions, and a con- 

 siderable variety of disinfectants. 



TESTING AND ANALYSIS OF DIPPING BATHS. 



The demand from bureau inspectors for field outfits for testing 

 dipping baths has greatly increased and the preparation and ship- 

 ment of such outfits has become an important part of the work of 

 this laboratory. During the calendar year 1914 the following sup- 

 plies of this character were sent out: One hundred and thirty new 

 test outfits for arsenic, in addition to 122 already sent out, making a 

 total of 252 in the field on January 1, 1915; supplies for making 

 arsenical tests in 1914, a sufficient quantity of the necessary materials 

 properly apportioned to make 32,000 tests; 58 new test outfits for 

 lime-sulphur dips, in addition to 3 previously sent out, making a 

 total of 61 in the field on January 1, 1915; supplies for testing lime- 

 sulphur dips, a sufficient quantity to make approximately 6,400 

 tests. During the year a field test for nicotin baths has been adopted 

 for official use, and supplies for this test are now being sent out. 



The studies of the changes in degree of oxidation of arsenic in dip- 

 ping baths in actual use in the field, which were continued from 

 last year, have been compiled and published as Department 

 Bulletin 259. To conclusions previously reported it may be added 

 that formaldehyde has been found to be effective in holding oxida- 

 tion of dipping baths down to a low figure, but it is believed that in 

 most cases it may be cheaper to let some of the arsenic go to waste 

 through oxidation rather than to use formaldehyde as a preservative. 



Some new methods for the analysis of lime-sulphur solutions and 

 dipping baths have been developed, with the object of obtaining more 

 exact quantitative knowledge of the precise combinations of sulphur 

 and of lime which exist in lime-sulphur dipping baths. 



Investigations have been made of the effect of the continued use of 

 hog-dipping baths under field conditions. The results show that 

 progressive loss of cresol follows such use and that serious diminution 

 of strength may be the final result. The desirability of a field test for 

 cresol dips is clearly indicated. A method for the field testing of 

 cresol dips has been devised and is now being subjected to field test. 



DISINFECTING HIDES. 



A bacteriological study of methods for disinfecting hides against 

 anthrax was continued and completed. The conclusions arrived at 

 were briefly as follows : 



The Seymour-Jones method of disinfecting with mercuric chlorid 

 and formic acid was found to be inefficient when the i^roportions of 



