116 ANNUAL REPORTS OP DEPARTMENT OF AGRICULTTJEE. 



208,000 arsenical tests, 31 test outfits for lime-sulphur dips, supplies 

 for making 5,900 lime-sulphur tests, supplies for 2,100 nicotin tests. 

 In addition supplies for more than 300,000 tests were sent out during 

 the first six months of 1917. 



Laboratory investigations have been made of the suitability of 

 various commercial forms of sodium carbonate for use in preparing 

 arsenical solutions. Certain other forms may be used in place of 

 sal soda under proper control. A report has been made and advice 

 will be sent to the field forces. 



A modified procedure for preparing " self-boiled " arsenical solu- 

 tion, intended to make the process shorter and more certain, has 

 been developed and. is being tried in the field. 



Further work has been done upon the disinfection of hides. Fur- 

 ther studies of the disinfecting value of mercuric chlorid under dif- 

 ferent conditions have been made, and it has been found that this 

 substance in a solution of 1 to 5,000 applied to hides for six days 

 is sufficient to destroy the infection of anthrax on the hide, provided 

 this soaking is followed by five days' exposure to limes of the usual 

 strength. It has further been found that the effectiveness of mer- 

 curic chlorid is influenced by sodium chlorid, which in amounts up 

 to 2 per cent aids the action of the mercuric chlorid, while more than 

 2 per cent appears to hinder its action. Although hides may be 

 disinfected by exposure to 1 to 5,000 mercuric-chlorid solution for 

 six days followed by five days' exposure in the limes, this method 

 does not serve satisfactorily to disinfect the effluent of the plant. 



Extensive studies have been made of various methods for treating 

 the effluent of tanneries so as to eliminate the danger of the dissemi- 

 nation of anthrax. The experiments with the use of chlorin gas 

 indicate that 50 parts of the gas per million parts of the effluent 

 is not efficient for disinfecting tannery effluents, the amount of 

 chlorin required being in most cases probably from 300 to 400 parts 

 per million of effluent. It appears that exhaust steam from tanneries 

 may be used effectively to sterilize the effluent. Numerous experi- 

 ments have shown that momentary heating at 100° C. (212° F.) 

 destroys the anthrax spores in infected soak water from hides. 

 Further work is being done along this line, as thfe observations made 

 in the bureau laboratories indicate that the anthrax spore is killed 

 by a shorter exposure in boiling water than has been reported by 

 other observers. The disinfection of tannery effluents by heat and 

 by chlorin has been studied in cooperation with the sanitary en- 

 gineer attached to the Meat Inspection Division. 



STUDIES OF CHANGES IN MEATS DURING STORAGE. 



For the most part the work on the changes in meats during storage 

 has consisted of a study of the enzj^ms which occur naturally in 

 muscular tissue. Exact knowledge of such enzyms is of fundamental 

 importance in a consideration of the changes that take place in 

 meats during storage. Two problems were studied — (1) the function 

 of muscular tissue in urea formation, and (2) the glycolytic prop- 

 erties of muscular tissue. The results of studies of the former indi- 

 cate that although there is a very considerable accumulation of the 

 precursors of urea in muscular tissue during autolysis, urea itself 

 is not formed. These facts indicate that muscular tissue is probably 



