48 MEAT EXTRACTS. 



The conclusions reached by the various investigators may be sum- 

 marized briefly as follows: Gelatin can replace proteid only in part 

 (Voit, Oerum, Pollitzer); it has, however, a high proteid-sparing 

 effect, whether fed alone (Kirchmann, Krummacher), or with other 

 foods (Voit, Oerum, I. Munk, Kauffmann, Rona and Muller) in infant 

 feeding (Gregor), or in convalescence (Brat, Mancini) ; this proteid- 

 sparing effect is exerted also by gelatin-peptones (Ganz, Gerlach) 

 and gelatoses (Brat). 



MEAT EXTRACTS AND JUICES. 



The various protein bodies and amido acids are so closely asso- 

 ciated that it is impossible to produce amido acids without produc- 

 ing albuminoses and peptones. Consequently, every commercial 

 meat extract must consist partly of albuminoses, peptones, etc. The 

 best extracts on the market to-day contain about 50 per cent of the 

 total nitrogen in the form of meat base nitrogen. When a meat 

 preparation contains only a small amount of its nitrogen in the form 

 of meat base nitrogen, the term " extract" seems to be no longer 

 applicable. And it is evident that the product represents much less 

 meat than an extract with 50 per cent of its nitrogen in the form of 

 meat base nitrogen, provided the total nitrogen in both cases is 

 approximately equal. Moreover, it is necessary to distinguish 

 between a meat extract containing large amounts of stimulating amido 

 acids and relatively small percentages of albumoses, peptones, and 

 insoluble proteid matter, and an extract (or, more properly, a meat 

 product) which consists largely of albumoses, peptones, and insoluble 

 matter and relatively small amounts of amido acids. The food value 

 of this last group of products is undoubtedly greater than that of the 

 former group, but they should not be classed as extracts because 

 of their different nature. The value of the amido bodies as food is 

 uncertain, but at least they furnish energy to the body. It appears, 

 therefore, that the value of meat extracts lies principally in their stim- 

 ulating qualities, the active principles of tea and coffee being on a 

 similar basis. 



The question of the nutritive value and relative worth of the vari- 

 ous nitrogenous constituents of meat preparations is a much-dis- 

 cussed but unsettled problem. Beef juice prepared from fresh beef 

 by pressure and heating and used unchanged is an ideal product, 

 containing the extractives as well as a large amount of nutritive 

 material. As a commercial product, however, it is impracticable. 

 The higher forms of nitrogen, insoluble proteids, alkali and acid albu- 

 mins, and coagulable proteids, as well as the unchanged proteids, are 

 the most desirable forms for the healthy individual. The invalid 

 may require partly digested proteids, such as proteoses and peptones. 

 A large amount of nitrogen in this form should be avoided, as many 



