PRINCIPAL PHYSIOLOGICAL TESTS. 17 



means of the mercury manometer recording on the drum of a 

 kymograph. 



Animals preferred. — Dogs, on account of their greater resisting 

 powers and their closer resemblance to man in responding to drugs, 

 are usually preferred for this class of work, although rabbits are very 

 serviceable. Cats are not so sensitive but are preferred b}^ Elliott. 



Principal reference literature. — Details regarding the preparation of 

 the animal as to the mechanical carrying out of the experiment can be 

 found in Essentials of Experimental Physiology, by T. G. Brodie, 1898, 

 p. 168; Klein, Burton-Sanderson, and Brunton, Handbook for the 

 Physiological Laboratory; T. Sollmann, Textbook of Pharmacology, 

 2d ed., 1906, pt, 3; Pembry, Beddard, Edkins, Hill, McLeod, and 

 Pembry, Practical Physiology; E. Cyon, Methodik der physiolo- 

 gischen Experimente und Vivisection; O. LangendorfT, Physiolo- 

 gische Graphik; Edmunds and Cushny, Laboratory Guide in Experi- 

 mental Pharmacology; Hermann, Experimental Pharmacology; H. 

 C. Wood, jr., Description of the Methods of Investigating the Action 

 of Drugs, International Clinic, vol. 4, p. 12, 1902; D'Arsonval, 

 Gabriel, Chaveau, and Marey, Traite de Physique Biologique; R. 

 Tigerstedt, Lehrbuch der Physiologie des Kreislaufes. 



Data concerning the anatomy of the dog, the rabbit, and the cat 

 can be found in Ellenberger and Baum, Anatomie des Hundes; W. 

 Krause, Anatomie des Kaninchens; St. George Mivart, The Cat, 



The large Handbuch der experimentellen Pathologie und Phar- 

 makologie of Heinz deals with results rather than with details of 

 methods. There are, however, a few points which are not usually 

 mentioned. 



Apparatus. — We have been dissatisfied with the ordinary kymo- 

 graph driven by a spring, on account of the variation in speed and 

 the necessity for frequent winding. In the case of the expensive 

 Hurthle machine this objection does not hold. For this reason the 

 writer has used an electric kymograph — the one described by him in 

 American Medicine, 1904, volume 8, page 405. This kymograph can 

 be easily made in most machine shops, as the wheels are stock cut. 

 The machine requires very little attention and the paper winds regu- 

 larly and does not sag. The kymograph made by Blix° also over- 

 comes many of the usual difficulties. The speed of the kymograph 

 should be kept uniform and should be noted. 



The time markers which have given the most satisfactory results 

 are those described by Marvin 6 under the name " Magnet for record- 

 ing sunshine and rainfall." This by slight modification can be made 



a Blix, M. Neue Registrirapparate. Arch. f. Gesam. Physiol. . vol. 90. p. 405. 1902. 

 & Marvin, C. F. Aneiuometry. U. S. Dept. Agr., Weather Bureau, Circ. D, Instru- 

 ment Div., 2d ed., 1900, p. 47. 



112 



