CHANGES IN FRESH BEEF DURING COLD STORAGE. 27 



Amijio nitrogen. — In the course of 100 days of autolysis the amino 

 nitrogen has increased from 2.24 per cent to 18.86 per cent of the 

 total nitrogen, or from less than one-tenth to more than one-half of 

 the total soluble nitrogen. 



Insoluble phosphorus. — The ratio of insoluble phosphorus to total 

 phosphorus is seen to be a decreasing function of the time of incuba- 

 tion, and while the rate of decrease is not entirely regular it will be 

 seen that, on the whole, the rate diminishes as the incubation period 

 is extended. At the end of the one-hundredth day of incubation but 

 1.76 per cent of the total phosphorus remains in insoluble form, as 

 against 20.16 per cent originally present. These changes may be 

 considered as due to the action of the enzyms lipase and nuclease 

 upon the phosphatids and nucleic acids, respectively. 



Total soluble phosphorus. — The changes in the ratio of total solu- 

 ble phosphorus to total phosphorus are naturally equal and opposite 

 to corresponding changes in the ratio of insoluble phosphorus to total 

 phosphorus, and have no further significance. 



Soluble organic phosphorus. — The figures for the ratio of soluble 

 organic phosphorus to total phosphorus are peculiar, in that during 

 the first seven daj^s of autolysis this ratio decreased from its initial 

 value of 23.87 per cent to its minimum value of 3.64 per cent. This 

 large initial decrease, however, should not be regarded with sus- 

 picion, since the continued increase in soluble inorganic phosphorus 

 indicates the continued cleavage of organic phosphorus that one 

 would expect. It would appear, therefore, that after the first ener- 

 getic cleavage of the preformed soluble organic phosphorus com- 

 pounds, the activity of the phosphatase decreases, and that new solu- 

 ble organic compounds of phosphorus — cleavage products from the 

 insoluble fraction — accumulate at a rate that is sometimes greater 

 than the rate at which they are broken down by the phosphatase. 

 The possibility, of course, is not excluded that the accumulating phos- 

 phorus compounds are inherently less susceptible to the action of the 

 phosphatase than are those originally present in the fresh meat. 



Soluble inorganic phosphorus. — Exce]:)t in the case of samples Nos. 

 112 and 113, the ratio of soluble inorganic phosphorus to total phos- 

 phorus increases continuously throughout the experiment, until at 

 the end of tl)e one-hiindredtli (]:iy of autolysis it has attained ii value 

 of 02.50 per cent, as again.st its original value of 55.97 per cent — more 

 than three-fourths of the increase having taken place during the first 

 seen (lays of incubation. 



SUMMARY OF RESULTS OF AUTOLYSIS EXPERIMENTS. 



Tlie results of the autolysis exi;ei'inients repoi-ted in this paper may 

 be summarized as follows: 



1. Pliysical changes in tlie samples of muscular tissue Avere not 

 marked, even at the conclusion of the experiment, and consisted 



