PREFATORY NOTE. 



This little manual has been designed, especially, to meet the needs 

 of those students who desire to become physicians or teachers of sci- 

 ence. While not intended as an exhaustive treatise, it has been the 

 endeavor to concentrate a number of useful experiments into a small 

 compass. For a few of these experiments a somewhat special equip- 

 ment may be needed ; but the majority of them may be as easily per- 

 formed in a preparatory school as in a college, with a Httle experi- 

 ence and ingenuity on the part of the instructor. 



It has been the aim to explain clearly the essential steps of the ex- 

 periments and the reasons for them ; but, at the same time, to leave 

 opportunities for observation on the part of the students themselves, 

 and to have them record their own inferences of the phenomena ob- 

 served. 



In the preparation of this laboratory guide, the standard and recent 

 books and papers bearing on practical physiology have been largely 

 drawn upon, among which may be mentioned the works of Stirling, 

 Halliburton, Waller, Brunton, Foster and I^angley, Gamgee, Stewart, 

 Long, Hall, Chase, and others. 



In a sense, all physiology is comparative since we are dependent 

 upon the lower forms of animal life for much of otir knowledge of the 

 function of similar organs and parts in the higher ; but there are dif- 

 ferences of function in the different genera of animals, correlated with 

 differences in structure and mode of life. Wherever it has been prac- 

 ticable, in the text, these differences have been pointed out. 



P. A. F. 

 August, i8g8. 



