7-2 



ANIMAL CHEMISTRY. 



production of heat and of force may seem 

 to be connected together, with reference to 

 mechanical effects, yet the disengagement 

 of heat can in no way be considered as in 

 itself the only cause of these effects. 



All experience proves, that there is, in 

 the organism, only one source of mechani- 

 cal power; and this source is the conversion 

 of living parts into lifeless, amorphous com- 

 pounds. 



Proceeding from this truth, which is inde- 

 pendent of all theory, animal life may be 

 /iewed as determined by the mutual action 

 of opposed forces; of which one class must 

 je considered as causes of increase, (of sup- 

 ply of matter,) and the other as causes of 

 Mminution (of waste of matter.) 



The increase of mass is effected in living 

 larts by the vital force; the manifestation 

 3f this power is dependent on heat; that is, 

 jn a certain temperature peculiar to each 

 specific organism. 



The cause of waste of matter is the chemi- 

 cal action of oxygen ; and its manifestation 

 is dependent on the abstraction of heat as 

 well as on the expenditure of the vital force 

 "or mechanical purposes. 



The act of waste of matter is called the 

 ;hange of matter ; it occurs in consequence 

 of the absorption of oxygen into the sub- 

 stance of living parts. This absorption of 

 oxygen occurs only when the resistance 

 which the vital force of the living parts op- 

 poses to the chemical action of the oxygen 

 is weaker than that chemical action ; and 

 this weaker resistance is determined by the 

 abstraction of heat, or by the expenditure in 

 mechanical motions of the available force 

 of living parts. 



By the combination of the oxygen intro- 

 duced into the arterial blood with such con- 

 stituents of the body as offer no resistance 

 to its action, the temperature necessary for 

 the manifestation of vital activity is pro- 

 duced. 



From the relations between the consump- 

 tion of oxygen on the one hand and the 

 change of matter and developement of heat 

 on the other, the following general rules may 

 be deduced. 



For every proportion of oxygen which 

 enters into combination in the body, a cor- 

 responding proportion of heat must be gene- 

 rated. 



The sum of force available for mechanical 

 purposes must be equal to the sum of vital 

 forces of all tissues adapted to the change 

 of matter. 



If, in equal times, unequal quantities of 

 oxygen are consumed, the result is obvious, 

 in an unequal amount of heat liberated, and 

 of mechanical force. 



When unequal amounts of mechanical 

 force are expended, this determines the ab- 

 sorption of corresponding and unequal quan- 

 tities of oxygen. 



For the conversion of living tissues into 

 lifeless compounds, and for the combination ; 

 of oxygen with such constituents of the i 



body as have an affinity for it, time is re- 

 quired. 



In a given time, only a limited amount of 

 mechanical force can be manifested, and 

 only a limited amount of heat can be libe- 

 rated. 



That which is expended, in mechanical 

 effects, in the shape of velocity, is lost in 

 time; that is to say, the more rapid the mo- 

 tions are, the sooner or the more quickly is 

 the force exhausted. 



The sum of the mechanical force pro- 

 duced in a given time is equal to the sum of 

 force necessary, during the same time, to 

 produce the voluntary and involuntary mo- 

 tions ; that is, all the force which the heart, 

 intestines, &,c., require for their motions is 

 lost to the voluntary motions. 



The amount of azotized food necessary to 

 restore the equilibrium between waste and 

 supply is directly proportional to the amount 

 of tissues metamorphosed. 



The amount of living matter, which in 

 the body loses the condition of life, is, in 

 equal temperatures, directly proportional to 

 the mechanical effects produced in a given 

 time. 



The amount of tissue metamorphosed in 

 a given time may be measured by the quan- 

 tity of nitrogen in the urine. 



The sum of the mechanical effects pro- 

 duced in two individuals, in the same tem- 

 perature, is proportional to the amount of 

 nitrogen in their urine; whether the mecha- 

 nical force has been employed in voluntary 

 or involuntary motions, whether it has been 

 consumed by the limbs or by the heart and 

 other viscera. 



That condition of the body which is called 

 health includes the conception of an equili- 

 brium among all the causes of waste and 

 of supply; and thus animal life is recog- 

 nized as the mutual action of both; and ap- 

 pears as an alternating destruction and resto- 

 ration of the state of equilibrium. 



In regard to its absolute amount, the waste 

 and supply of matter is, in the different pe- 

 riods of life, unequal ; but, in the state of 

 health, the available vital force must always 

 be considered as a constant quantity, corre- 

 sponding to the sum of living particles. 



Growth, or the increase of mass, stands, 

 at every age, in a fixed relation to the 

 amount of vital force consumed as moving 

 power. 



The vital force, which is expended for 

 mechanical purposes, is subtracted from the 

 sum of the force available for the purpose 

 of increase of mass. 



The active force, which is consumed in 

 the body in overcoming resistance (in caus- 

 ing increase of mass) cannot, at the same 

 time, be employed to produce mechanical 

 effects. 



Hence it follows necessarily, that when, 

 as in childhood, the supply exceeds the 

 waste of matter, the mechanical effects pro- 

 duced must be less in the same proportion. 



With the increase of mechanical effects 



