374 EXPERIMENTAL PHARMACOLOGY 



of the special pieces of apparatus shown in Figs. 255 and 

 256 have been inserted into the chest the best results can 

 be obtained. The writer recommends that all laboratories 

 which can afford it build some such form of universal arti- 

 ficial respiration machine as those shown in Figs. 360 and 

 364 or that where both positive and negative air pressure is 

 already available to the laboratory a universal valve like 

 those shown in Figs. 365 and 366 be obtained. Cats can be 

 used very well for lung tracings by the aspiration method, 

 in fact in some respects they are better than dogs, but the 

 larger size and greater vitality of dogs make them prefer- 

 able as a rule. 



By one of the methods previously given arrange to take 

 a record of the bronchial muscle changes and to record the 

 right carotid blood-pressure. The arrangements for re- 

 cording blood-pressure should be completed first. The in- 

 jecting cannulas are next inserted and the burettes are filled 

 with ergamine solution (ten cubic centimeters equal one 

 milligram) and with adrenaline (1:10,000) or hordenine 

 (one cubic centimeter equals ten milligrams this can be 

 bought of Burroughs, Wellcome & Co. 1 gram $1.80, solu- 

 ble in water on heating). 



The chest is now opened (if this method is to be used) 

 and the apparatus is inserted (using positive artificial res- 

 piration). Two courses are now open as follows: 1st, If 

 positive artificial respiration (a hand bellows may be used 

 if nothing else is obtainable) must be used throughout the 

 experiment the tambour tube is now connected to the ap- 

 paratus in the chest and a record about three inches in am- 

 plitude on the drum should be arranged for by making the 

 proper magnification for the writing point, regulation of 

 the expansion of the lungs, etc. If one has a well-fitting 

 piece of apparatus in the chest he need not necessarily pith 

 the dog by this method but it is usually advisable to do so 

 to keep the animal quiet and to avoid the anesthetic. 2nd, 

 If negative artificial respiration can be used, then after the 



