GENERAL REVIEW OF THE INVESTIGATION. 99 



minor constituents as water, ash, etc., have served to show that for 

 the protein distribution there is a slight variation in the cold-stored 

 product from the fresh, and for the fat values a wide variation. 



(3) A histological examination of the muscle of both fresh and 

 cold-stored chickens shows a marked and a progressive change in 

 the structure of the fibers which is deep-seated and after long periods 

 renders the tissue almost unrecognizable. Selective microchemical 

 differentiation of the tissues confirms the chemical change found by 

 gross analytical methods. 



(4) A bacteriological examination of fresh and cold-stored chickens 

 reveals the presence of appreciable numbers of organisms, calculated 

 on the gram basis, in the edible portions of those preserved by cold, 

 though the numbers were not large. In fresh fowls the same tech- 

 nique gave no bacterial growth. 



GENERAL REVIEW OF THE INVESTIGATION. 



In reviewing the details of this preliminary work it must be remem- 

 bered that some of the inferences drawn may be modified by future 

 investigations, although the fact that certain changes take place in 

 the food materials examined after definite periods of storage is well 

 established both by the organoleptic and by the chemico-bacterio- 

 logical tests and is further confirmed, in the case of the chickens 

 examined, by the histological studies. 



The principal lines of investigation reported, namely, on eggs,, 

 quail, and chickens, conducted at Washington under known conditions 

 of storage, and the more complete study of chickens stored under 

 market conditions at Philadelphia, are summarized in the following 

 pages, brief reference also being made to the conclusions drawn 

 from the milk investigation previously reported by Pennington. 



ORGANOLEPTIC TESTS ON CHICKENS AND QUAIL. 



The general results of the organoleptic tests of the stored fowls and 

 birds leads to the conclusion, first, that even after three months, 

 before cooking, it is not difficult to distinguish, by the appearance, 

 color, and odor, a freshly killed bird from the one that has been in 

 cold storage. The shriveled condition of the eye and the skin and 

 the generally dilapidated appearance of the bird are very significant 

 and distinct. After cooking, however, within a period of three 

 months, there is much disagreement on the part of the jurors respect- 

 ing the proper classification thereof. This is especially true as to 

 distinguishing between the drawn and the undrawn birds, where the 

 variations in judgment are of such a character as to lead to the belief 

 that it is impossible within that time, from the taste, odor, and smell 

 of the cooked bird, to determine which one had been drawn and which 

 was undrawn at the time of storage. The possibilities of determining 



