334 EXPEKIMENTAL INVESTIGATION OF THE ACTION OF MEDICINES. 



Pig. 147. — Apparatus mentioned on preceding page, and which I employed in my 

 experiments made in 1871 for ascertaining the effect of heat and cold on the 

 vessels of the frog's lungs. A, a piece of cork to which the frog is fastened, 

 is laid on B, the stage of a microscope, and attached by an india-rubber strap, 

 C. D is a small ring of cork covered with a thin circle of glass. E is the 

 inflated frog's lung, f is a tube by which a current of air can be directed on 

 the frog's lung. It is held in position by a piece of wire, a, which can be 

 bent to any position, i is a flask containing ice and water, h, a flask con- 

 taining hot water. K is a three-way stopcock, by which a current of air may 

 be sent from the spray -producer, l and m, through either i or h at will, and 

 thus cold or hot air may be applied alternately to the lung. (Reprinted from 

 my Text Book of Pharmacology, Sfc. London : Macmillan & Co.) 



