PART FIFTH. 



Feeding with Sugar. 



WHAT becomes of sugar formed in the liver and carried to all Preliminary 

 parts of the body by the blood? What is its role? remarks. 



Sugar, as its composition shows, contains carbon, oxygen and 

 hydrogen. The carbon throws out in burning, or oxidizing, 

 carbonic acid, water and heat, which may be transformed into 

 work and energy. It is concluded from this that sugar produces 

 at least a portion of the animal heat, and recent experiments 

 show beyond cavil, that we must also look to the same material 

 for the muscular energy or work. 



It is to Mr. Chauveau that the credit is justly due for the en- 

 tire investigations upon this most important subject, as before 

 his time the theories advanced were certainly most erroneous. 



A celebrated authority such as Claude Bernard enunciated 

 the theory that sugar disappeared in the lungs. As early as 

 1856 Chauveau showed that there were traces of sugar in the Cnauveau's 

 entire arterial circulation which gradually disappeared in produc- theory, 

 ing heat. He enunciated his ideas about as follows: 



" Energy devoted to the production of work always means 

 muscular energy, and in all cases has for its principal starting 

 point the combustion of glycogen, with which the tissues of the 

 organs are impregnated. Blood becomes poorer in glucose, 

 during its general capillary circulation, and mainly in the mus- 

 cular tissues." 



Chauveau has shown that there existed a relation between 

 muscular energy, glycogen production and the destruction of 

 sugar in the blood. These investigations were mainly centered 



upon horses, showing the exchange that took place in the blood 

 passing through muscles at rest and during work. As an ex- 

 ample the muscles used during mastication and the glands se- 

 creting saliva were watched during this study. The law, which 



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