PHYSIOLOGY. 



PART IL-FDNCTIONS OF MUSCLE AND NERVE. 

 BY DR. MICHAEL FOSTER, 



INTRODUCTORY. 



IN the following part of this work, the object chiefly kept in 

 view has been to limit the directions as much as possible to 

 such observations and experiments as the student may be 

 reasonably expected to perform for himself under due super- 

 vision. The ordinary phenomena of muscle and nerve are 

 consequently dealt with at far greater length than are the 

 properties of the central nervous system. The latter are, to 

 sa}' the least, but imperfectly known, the experiments on which 

 our knowledge rests difficult and complex, and too often bring- 

 ing out uncertain or even contradictory results. The former, 

 on the other hand, may be studied with approximate exacti- 

 tude ; the methods of experiment and observation are becom- 

 ing, year by year, more physical in character, and the observa- 

 tions themselves, fundamental in their nature and having the 

 widest bearings in all the higher branches of physiologj^, may, 

 for the most part, be conducted on frogs, may be repeated any 

 number of times without difficulty or expense, and so serve 

 usefully as a means of training students in physiological study 

 and inquiry. The phenomena in question are so fully treated 

 of in various text-books, that space in the following chapters 

 has been devoted to detailed instructions as to how to proceed 

 in the various observations rather than to complete explana- 

 tions of what the observations are intended to show or prove. 



Instructions concerning the various special pieces of appara- 

 tus required in this part of the subject are thrown together, 

 for convenience sake, in the first chapter. The succeeding 

 chapters deal with the general properties of muscle and nerve; 

 while such observations as the student may be expected to 



