THE CHEMISTRY OF COOKERY. 363 



order to alter its raw flavor, a scum will be seen to rise upon the sur- 

 face ; this is carefully removed in the manufacture of Liebig's extract 

 or the preparation of beef -tea for an invalid, but in thus skimming we 

 remove a highly-nutritious constituent viz., the albumen which has 

 coagulated during the heating. The pure beef -tea, or Extractum Car- 

 nis, contains only the creatine, creatinine, the soluble phosphates, the 

 lactic acid, and other non-coagulable saline constituents, that are 

 rather stimulating than nutritious, and which, properly speaking, are 

 not digested at all i. e., they are not converted into chyme in the 

 stomach, do not pass through the pylorus into the duodenum, etc., but, 

 instead of this, their dilute solution passes, like the water we drink, 

 directly into the blood by endosmosis through the delicate membrane 

 of that marvelous network of microscopic blood-vessels which is spread 

 over the surface of every one of the myriads of little upstanding fila- 

 ments which, by their aggregation, constitute the villous or velvet coat 

 of the stomach. In some states of prostration, where the blood is in- 

 sufficiently supplied with these juices, this endosmosis is like pouring 

 new life into the body, but it is not what is required for the normal 

 sustenance of the healthy body. 



For ordinary food, all the nutritious constituents should be re- 

 tained, either in the meat itself, or in its liquid surrounding. Regard- 

 ing it theoretically, I should demand the retention of the albumen in 

 the meat, and insist upon its remaining there in the condition of tender 

 semi-solidity, corresponding to the white of an egg when perfectly 

 cooked, as described in No. 4. Also that the gelatine and fibrine be 

 softened by sufficient digestion in hot water, and that the saline juices 

 (those constituting beef -tea) be partially extracted. I say " partial- 

 ly," because their complete extraction, as in the case of the macerated 

 mince-meat, would too completely rob the meat of its sapidity. How, 

 then, may these theoretical desiderata be attained ? 



It is evident from the principles already expounded that cold ex- 

 traction takes out the albumen, therefore this must be avoided ; also 

 that boiling water will harden the albumen to leathery consistence. 

 This may be shown experimentally by subjecting an ordinary beef- 

 steak to the action of boiling water for about half an hour. It will 

 come out in the abominable condition too often obtained by English 

 cooks when they make an attempt at stewing an unknown art to the 

 majority of them. Such an ill-used morsel defies the efforts of or- 

 dinary human jaws, and is curiously curled and distorted. This tough- 

 ening and curling is a result of the coagulation, hardening, and shrink- 

 age of the albumen, as described in No. 3. 



It is evident, therefore, that in stewing, neither cold water nor 

 boiling water should be used, but water at the temperature at which 

 albumen just begins to coagulate i. e., about 134, or between this 

 and 160 as the extreme. But here we encounter a serious difficulty. 

 How is the unscientific cook to determine and maintain this tempera- 



