FOODS AND CONDIMENTS 169 



Very little truly scientific work 1 has as yet been accomplished in 

 this field; so that we must content ourselves with indicating the 

 problem.* 



Meat. What we consume as " meat " consists for the most part 

 of muscle fibers and connective tissue with the interspersed fat. In 

 judging the meat of healthy animals its source is the chief criterion; 

 young, well-nourished animals possess a juicy meat and tender con- 

 nective tissue, whereas old worn-out animals are less juicy and their 

 connective tissue shows a firmer structure. From these few premises 

 it is evident that it is a question of turgor and swelling capacity, 

 which change with age; this is an important colloid-chemical prob- 

 lem. It is still an open question whether the toughening of con- 

 nective tissue may be compared to the lignification of the vascular 

 bundles of plants, which according to H. WISLICENUS* (see pp. 249 

 and 250) is due to the adsorption of colloids from the cambial sap. 



Fresh killed meat is tender; it becomes soft again only upon the 

 disappearance of rigor mortis. This is conditioned by phenomena 

 of swelling and shrinking, an interesting method for studying meat 

 adopted by O. VON FURTH and E. LEUK. After death lactic acid 

 accumulates in the muscular tissue, and greatly increases the swell- 

 ing capacity of the muscles (see p. 290). If such a muscle is 

 placed in a dilute salt solution it swells up and after about 25 

 hours has taken up a maximum amount of water of swelling. Then 

 shrinking occurs as the result of the progressive coagulation of the 

 muscle albumin. The curve obtained in this manner has a quite 

 characteristic shape depending on what has happened to the meat. 

 Fig. A shows the curve of swelling of horse heart three or four 

 hours after slaughter; Fig. B, after it has been kept 3 days in the ice 



1 In this connection Dr. J. G. M. BULLOWA mentions favorably " The Chemistry 

 of Cookery," by MATTIEU WILLIAMS, London, Chatto & Windus, 1892. [H. C. 

 SHERMAN has included in his book, " Food Products," Macmillan Co., 1917, the 

 important recent data. By reason of the war, the preservation of perishable food- 

 stuffs has assumed great importance. Dehydrating processes make possible the 

 transportation of large quantities of vegetables in limited cargo space. CLARENCE 

 V. EKROTH has presented an excellent account of the methods and literature of dry- 

 ing and dehydrating foods in ALLAN ROGERS' " Manual of Industrial Chemistry," 

 Van Nostrand, 1918. The products dried by EKROTH'S " G. H." Evaporator in 

 the Mrs. OLIVER HARRIMAN'S Food Research Laboratory are of excellent quality; 

 are said to retain the important food accessories. The " G. H." Dehydrator dries 

 its product in moist air at a moderate temperature. Humidity and temperature 

 are controlled. A fan blower is provided for recirculation of the air so that 

 volatile substances are kept in contact with the product and only a small per- 

 centage is lost. The process is quite the reverse of ordinary cooking when an 

 effort is made to retain moisture and volatile substances by rapidly sealing the 

 surface of the food by quick heat coagulation. Tr.] 



