THE STRUCTURE OF THE MOTOR ORGANS 91 



are coagulated and left behind in the meat; even if cooking be com- 

 menced by soaking in cold water the myogen still remains, as it is 

 as insoluble in cold water as in hot. Beef tea as ordinarily made, 

 then, contains little but the flavoring matters and salts of the 

 meat, traces of some albumins and some gelatin, the latter derived 

 from the connective tissues of the muscle. The flavoring matters 

 and salts make it deceptively taste as if it were a strong solution 

 of the whole meat, and the gelatin causes it to "set" on cooling, so 

 the cook feels quite sure she has got out "all the strength of the 

 meat," whereas the beef tea so prepared contains but little of the 

 most nutritious protein portions, which in an insipid shrunken 

 form are left when the liquid is strained off. Various proposals 

 have been made with the object of avoiding this and getting a 

 really nutritive beef tea; as for example chopping the raw meat fine 

 and soaking it in strong brine for some hours to dissolve out the 

 myogen ; or extracting it with dilute acids which dissolves the myo- 

 gen and myosin and at the same time render it non-coagulable by 

 heat when subsequently boiled. Such methods, however, make un- 

 palatable compounds which invalids will not take. Beef tea is a 

 slight stimulant, and often extremely useful in preparing the stom- 

 ach for other food, but its direct value as a food is slight, and it 

 cannot be relied upon to keep up a patient's strength for any 

 length of time. There can be no doubt that thousands of sick 

 persons have in the past been starved to death on it. Liebig's ex- 

 tract of meat is essentially a very strong beef tea; containing much 

 of the flavoring substances of the meat, nearly all its salts and the 

 crystalline nitrogenous bodies, such as creatine, which exist in 

 muscle, but hardly any of its really nutritive parts, as was pointed 

 out by Liebig himself. From its stimulating effects it is often 

 useful to persons in feeble health, but other food should be given 

 with it. It may also be used on account of its flavor to add to the 

 ''stock" of soup and for similar purposes; but the erroneousness 

 of the common belief that it is a highly nutritious food cannot be 

 too strongly insisted upon. Under the name of liquid extracts of 

 meat other substances have been prepared by subjecting meat to 

 chemical processes in which it undergoes changes similar to those 

 experienced in digestion: the myosin is thus rendered soluble in 

 water and uncoagulable by heat, and such extracts if properly pre- 

 pared are nutritious and can often be absorbed when meat in the 



