18 EXPERIMENTAL PHYSIOLOGY 



is the method, the technique, through which the facts are observed. 

 The technique guides one's hands and senses in the study of new 

 phenomena, while the principles already mastered guide one's mind 

 in dealing with the facts of the new phenomena. The hand and the 

 mind working with technique and principles make the equipment 

 of the scientific man of to-day. 



As the application of this general method of the presentation of 

 physiology, it may be briefly stated that, so far as the time permits, 

 the student discovers for himself the facts and draws his own con- 

 clusions, defending them against the criticism of others. This is 

 supplemented by demonstrations to the class, in which each student 

 can observe phenomena which later become the subject of general 

 discussion. Limitations in the time that may be devoted to work 

 in the laboratory make it necessary to occasionally discuss phenomena 

 and principles which the student has not observed and formulated; 

 but these discussions have the purpose of permitting a more systematic 

 presentation of the subject than would otherwise be possible, and 

 the student s held responsible finally for what he has observed only. 



Regarding Illustrations. The profuse illustration of a text-book 

 is in perfect accord with the principles of pedagogy; that the profuse 

 illustration of a laboratory manual is the reverse is evident from 

 the following considerations: 



The laboratory student receives from the demonstrator the material 

 with which he is to work. If he receives a piece of apparatus which 

 is new to him, a few questions or hints in his laboratory manual 

 will lead him to discover, from an examination of the apparatus 

 itself, the physical and mechanical principles involved and utilized 

 in it. Most students will spontaneously make drawings showing 

 the essential parts of all instruments ; all students will willingly do so 

 if required. This is a most valuable exercise for the pupil, which 

 is likely to be omitted if the manual contains cuts of the apparatus. 



Nearly every exercise requires the preparation of some simple 

 appliance e. g., a frog board or a recording lever whose adjust- 

 ment will be much facilitated if the student is guided by a figure in 

 his manual, but a model which the demonstrator has set up will be 

 a better guide. 



I have often seen students read their text descriptive of some 

 organ e. g., a frog heart and verify its statements from the accom- 

 panying figures, leaving almost unnoticed the object itself, which 

 lay before them. A few brief questions or hints would have led 

 them to discover from the object all of its essential features. Dia- 

 grammatic anatomical figures are sometimes useful in a laboratory 

 manual, but true anatomical pictures are worse than useless they 

 bar the student's independent progress. If his laboratory manual 

 contains illustrations of all apparatus and tissues, and of such experi- 

 ments as admit of graphic records, the student makes similar draw- 



