MUSCLES. 425 



Alcohol-extract from 1U<) parts of recent frog's flesh. 



The amount of fat was unaffected. No urea could be found 

 in the alcohol-extract. 



There is great difficulty in performing experiments of this 

 nature on warm-blooded animals in consequence of the rapidity 

 with which isolated portions of muscle lose their irritability. 



The best results were obtained with decapitated pigeons. 



a. In electrized muscle, b. In non-electrized muscle. a : b 

 Albumen . . 2-04 2-13 



Water-extract . 0-64 0-73 0-88 : 1 



Spirit-extract . 1-68 1-58 1-06 : 1 



It remains to be considered whether the fibrin takes part in 

 this decomposition : a priori we should infer that it did, for 

 the protein-compounds seem universally the conductors of the 

 highest vital energies, and further the increased amount of sul- 

 phates and phosphates in the urine after muscular exertion indi- 

 cates a decomposition of the sulphur and phosphorus compounds. 



The above facts sufficiently show that muscular action is 

 always accompanied by a chemical change in the composition of 

 the acting muscle.] 



The Brain, Spinal Cord, and Nerves. 



Chemical analyses of the brain, spinal cord, and nerves are 

 not calculated to throw much light on the functions of the 

 nervous system in relation to the animal organism. 



According to the analyses of Couerbe, the mass of the brain 

 contains five different sorts of fat, viz. cholesterin, eleencephol, 



