132 APPENDIX 



derangement and damage by cooling, inspissation, drying, and the blocking of vessels and 

 cannulae by clots or mucus. The student whose sole experience is with the frog hardly 

 realizes the delicacy in some respects of the tissues of mammalian life. With frog prepara- 

 tions the omission to get ready the inductorium or mechanical apparatus before exposing the 

 animal tissues can be repaired by allowing the latter to lie waiting although ready, 

 because temperature and even evaporation changes are often too slight and slow to matter 

 much ; but with the warm-blooded preparation such a mistake is apt to be fatal. 



A fact which is surprising, but meets, I fancy, most teachers and examiners, is that a 

 student who may have quite satisfactorily performed some experiment from his practical 

 course is yet, on questioning him, found to be unaware of the point which the experiment 

 inculcates. Hence in the instructions for the present course the succinct mention at the 

 head of each exercise of what the exercise aims at. Short statements concerning the 

 history of some of the experiments followed in the exercise are, partly for the same purpose, 

 appended to the exercise. These ' annotations ' contain a certain number of references to 

 original sources, with a view to helping and encouraging the student to seek such sources 

 either in the Departmental or in the University library. 



The sequence of arrangement of the successive exercises in the following pages is one 

 which has been found appropriate ; but it is open to wide modification without real impair- 

 ment of the efficacy of the course. As arranged, the exercises on organs isolated from the 

 body in a surviving state are taken first ; then those on the circulation, commencing with 

 the Harvey observations by inspection, i. e. the simplest method ; then those on respiration 

 and secretion ; then those on the central nervous system ; and finally the experiment on 

 phagocytosis and the opsonic action of serum. The experiment on the pancreas and secre- 

 tin is placed late because exposure of the pancreatic duct makes some demand on skill the 

 student will have acquired. On the other hand, the exercises on phagocytosis and opsonins, 

 and that illustrating the treatment of haemorrhage by transfusion of gum-saline, are placed 

 late as bridging toward Pathology, a subject which the student will pursue next after his 

 physiological course is finished. 



B. BEMAUKS ON THE PRACTICAL CONDUCT OF 

 INDIVIDUAL EXERCISES 



EXERCISE I 



A suitably slow speed of travel of the recording-surface for registering the beat of the 

 intestine-strip or arterial wall presents difficulty with some patterns of student's drum. 

 This can be obviated by use of the small speed-reducing pulley (text-fig. 43) clamped to the 

 table-edge or to a firm vertical standard on the table. The pulley figured reduces the 

 revolution number eighty times. It is simple and can transfer ample power. It replaces, 

 and at smaller cost, the slow-gear attachment which must otherwise be provided as fixture 

 to the recording-drum itself. It is more accurate than some of the expensive slow-gears 

 supplied with the drums, and less liable to get out of order. Being at some distance from 

 the recording-drum and preparation, it is less exposed to getting splashed and corroded. If the 

 delivery pulley be given a double groove it will drive two recording-drums at once, thus sup- 



