BIOLOGY. 281 



it is supplied with blood ; and also looked upon the muscular, as 

 well as the nervous, system, as an entire independency, — the 

 muscular system, nourished by blood and charged with caloric 

 as caloric ; the nervous system, similarly nourished, and charged 

 with caloric in its electrical modification. If the systems be 

 conjoined, the result of their equilibrium is a simple passive 

 state, while the result of a disturbance of their equilibrium is mo- 

 tion and sensation. These ideas have been confirmed by the ex- 

 periments or the action of cold referred to in the preceding article 

 (pp. 278-280), the apparent death being changed to life by the 

 restoration of caloric. He draws the following inference in re- 

 gard to sleep : '* I take it that during sleep the exhausted brain, 

 nerve-cord, or entire nervous system, everywhere takes up and 

 stores up caloric, and so continues to take up and store up until it 

 is charged to its full capacity. Then, if I may use such expres- 

 sion, it overflows with force, it spontaneously fills the body, and 

 there is presented that phenomenon of motion which we call 

 ' awakening.' Send other force, vibration from noise or mechani- 

 cal motion, at any moment through a sleeping body, and you may, 

 through a dynamic act, excite motion, and the body may awake ; 

 but by this you have not primed the body with the force it wants 

 for sustained work ; j'ou passed a charge of force through it, but 

 vou did not charge it. So when my unwound watch is ceasing, 

 1 can stimulate it into movement for a moment or so by a moder- 

 ate blow or shake ; but the force is applied uselessly if the main- 

 spring be not recharged." — Med. Times and Gazette. 



WOKK AND FOOD. 



The researches of Fick, Wislicenus, Frankland, and others have 

 been given in the " Annual of Scientific Discovery " for 1866, 67, 

 pp. 286-292, and 1868, p. 245 ; since then Dr. Parkes has found 

 that during a period of work a man excretes less nitrogen than 

 during a period of rest, whether he feeds on nitrogenous food or 

 carbonaceous only. He also finds that after nitrogenous food has 

 been cut off from the system and again supplied, there is a reten- 

 tion of that nitrogen, showing that it is needed to fill up some 

 waste ; also that, during the first rest after exercise, where nitro- 

 genous food has not been cut off, there was an increase in the 

 elimination of nitrogen. Xo theory of the relation of food, mus- 

 cle, and work can be now tenable which does not account for 

 these facts. 



His own view is that, when a voluntary muscle is brought into 

 action by the will, it appropriates nitrogenous matter and grows ; 

 the stimulus or the act of union gives rise to changes in the non- 

 nitrogenous substances surrounding the ultimate elements of the 

 muscular substance which cause the conversion of heat into mo- 

 tion. The contraction continues until the effete products of these 

 changes arrest it (as they have been shown to do by Ranke and 

 others), a state of rest ensues, during which time the effete prod- 

 ucts are removed, the muscle loses nitrogen, and can again be 



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