246 ANNUAL REPOKTS OF DEPARTMENT OF AGRICULTURE. 



The presence of this foreign material is noted where a certain t3q)e 

 of (lehairing machine is used and the hogs pass through it head up. 

 The liair and dirty wash water enter the sticker's wound and gain 

 entrance to the liver through the heart and posterior vena cava. The 

 objectionable condition can be overcome by requiring that the hogs 

 pass through this type of machine head down and that the practice of 

 pumping back dirty wash water and applymg it to carcasses be dis- 

 contmued. This finding has resulted m an order directing that all 

 livers contaminated in the manner indicated above be condemned. 



The study of the efl'ect of prolonged storage on canned meats has 

 been continued. During the past year a careful cliemical, histo- 

 logical, and bacteriological study has been made of the different 

 classes of canned meats in storage, and the remainder of the samples 

 are being held for later examination. A part will be examined during 

 the coming fiscal year and others will be stored for a still longer time. 

 The results so far are not of sufficient importance nor are they suffi- 

 ciently well substantiated to warrant a detailed report. 



In addition to the lines of work reported above, a considerable 

 amount of time has been given to the consideration of the questions of 

 less importance, such as the solubility of paraffin and sulphur in lard, 

 the production of formaldehyde by heatmg concentrated cane sugar 

 solution, the suitability of silicate and shellac as protective coverings 

 for galvanized containers, and a study of the constituents of meat 

 extracts and of extracts made from organs with a view to identifying 

 these either alone or in mixture. A refrigerating machine was in- 

 stalled and a few cold-storage rooms were constructed prefiminary to 

 study of the effect of cold storage on meats. 



DIPS AND DISINFECTANTS. 



It was stated in last year's report that a formula had been evolved 

 for a concentrated arsenical dip for tick-eradication work and that 

 the preparation was undergoing practical tests in the field. The 

 results of these tests were satisfactory, and as a consequence the 

 preparation of this dip for limited use by bureau employees m the field 

 has become a part of the routine work of the laboratory. Thus far a 

 sufficient amount of this dip has been sent out to make over 30,000 

 gallons of diluted dipping bath. 



The arsenical dip employed for cattle has been the subject of some 

 study tliroughout the year along such lines as a search for forrnulas 

 wliich will afford a concentrated dip, the best method for obtaining 

 a good tar emulsion, the applicability of hard waters for preparing 

 the dip, and certain precautions necessary for obtaining complete 

 solution of arsenic. The work has enabled the laboratory to make 

 some suggestions of value in the preparation of such dips. 



As a result of the analysis of certain samples of arsenical baths in 

 which cattle had been dipped, it was discovered that under certain 

 conditions arsenious solutions prepared by boiling arsenious oxid with 

 sodium carbonate are subject to oxidation, so that after several weeks 

 nearly all the arsenic is to be found in the form of salts of arsenic acid. 

 The cause of the change appears attributable to bacterial activity. 

 An account of the work done in studying the change and in tracuig its 

 cause has been prepared for publication. 



For a number of reasons it appears desirable that the bureau should 

 have knowledge of the degree of absorption or retention of arsenic 



