106 PRELIMIXAEY COLD STORAGE STUDIES. 



Chickens may be. for instance, prepared for shipment at distant 

 points and sent in refrigerator ears either frozen or at a low tem- 

 perature on a voyage recmiring a long period of time before they 

 finally reach the depot in which they are preserved until a demand for 

 consumption arises. It was necessary, therefore, in aU studies of 

 market chickens to begin the work with fowls whose history was 

 known so that they could be followed, not only from the time of 

 slaughter, but even before that time. The different breeds to which 

 the chickens belong, the methods of hatching and raising, the charac- 

 ter of the feed which they eat — all may have important bearings upon 

 histological and chemical, as well as upon bacteriological, data. Hence 

 the desirability of the practice which was finally adopted, not only 

 of studying chickens in a commercial way. but also of having those 

 of known breed and history. 



Manifestly it was impracticable to study microscopically all of the 

 edible parts of the bird at this time, hence it was decided to select 

 for comparative work the fibers of the large muscle of the breast, 

 the Ptctoralis major, which is usually considered the choicest food 

 portion, and which is apparently the part which keeps longest and 

 best. In order that the character of the changes may be more 

 readily appreciated, they have been reproduced by microphoto- 

 graphs and by colored plates, so that the reader who is not skilled 

 in microscopic work nor in histological investigations may be able to 

 see at a glance the character of the changes which have taken place. 

 See Pis. YI to XL The sinuous outline of the fresh fibers soon dis- 

 appears in cold storage, and the fibers are not by any means so flex- 

 ible as they were in the fresh state. The most obvious change,, 

 however, which takes place during this interval is manifested as a 

 structureless, granular substance which lies between the individual 

 fibers and between their aggregations which are known as bundles. 

 The origin of the substance is in the fiber itself, and in the earlier 

 periods of storage its composition, according to reactions obtained 

 with various selective dyestuffs which afford excellent microchem- 

 ical reagents, is not very different from that of the normal fiber. 

 As the storage period is lengthened, however, most marked differ- 

 ences between the normal and cold-stored tissues, as exhibited in the 

 staining reactions, make their appearance, and such changes, whether 

 referable directly to bacterial or enzymic action, are essentially 

 chemical, and deal with the fundamental principles composing flesh 

 foods. The results obtained from this microscopic study of the his- 

 tology of market cold-stored fowls would seem to point the way to a 

 series of investigations, which has already been begun and from 

 which it is believed will accrue a knowledge of the obscure chemical 

 changes undergone by protein, to elucidate which the present gross 

 chemical methods are entirely inadequate. 



