10 PRELIMINARY COLD STORAGE STUDIES. 



cerned, the tissues are almost as well preserved as if they had been 

 completely sterilized and subsequently protected from any external 

 infection. That changes, however, do go on, even in frozen bodies, 

 is incontestable. The nature of these changes, the method by which 

 they are effected, and the results produced are, therefore, all legiti- 

 mate fields of inquiry in attempting to carry out the will of Congress. 

 It is evident, then, that the changes which take place are of the fol- 

 lowing character: 



First. There may be bacterial or enzymic action taking place in a 

 very limited degree and yet of sufficient magnitude in the course of 

 time to produce distinct results. Therefore, one line of investigation 

 must evidently be directed to the ascertainment of any changes of 

 this character. 



Second. The activity of the organisms above mentioned must 

 necessarily produce changes in chemical constitution which may 

 affect very markedly the nutritive properties and, to that extent, the 

 wholesomeness of the food products. Careful chemical examina- 

 tions of the food products in a fresh state as they are entered at 

 the cold-storage warehouses and also a similar examination on their 

 withdrawal at different intervals are, therefore, necessary. The 

 object of these examinations is, of course, to determine the nature 

 and extent of the chemical changes produced. 



Third. From the action of the above agencies it is evident also that 

 changes in the actual construction of the tissues may be expected. 

 These changes, which are known scientifically as histological changes, 

 are not evident in their incipient state to the senses, and therefore 

 can only be detected by careful microscopic examination. Special 

 microscopical studies have therefore been made in the investigations, 

 an account of which is to follow. 



Fourth. The effects of storing certain food products, such as fowls 

 and game birds, without removing the contents of the body cavity, 

 as compared with changes which go on after removing such waste 

 material, present a problem of great interest in connection with the 

 examination. To this end, in the case of fowls and game birds, 

 examinations were made of those stored after drawing (which is the 

 technical term used for the removal of the entrails) , and also of those 

 stored without drawing. Birds of as nearly as possible the same age 

 and in the same condition were stored in both the drawn and the 

 undrawn state and removed from storage from time to time for 

 examination. 



Fifth. Among the most important of the changes which may take 

 place in cold storage are those which relate to organoleptic properties 

 of the foods. The color, odor, taste, tenderness, etc., of these food 

 products have much to do with tb^ir value as food and with their 

 effect upon health and digestion. To this end careful studies were 



