160 REPORT 1871. 



tically noted, (e) The animals were placed for narcotism iu the small gLiss 

 chamber now before the Members. The chamber as it is was finally con- 

 structed, after many essays, by my friend Dr. Sedgwick, and it answered 

 admirably. The animal was placed, without any restraint, iu the chamber ; 

 one foot was then gently drawn out on to the stage attached to the 

 chamber, and the web was extended over the small glass plate. The 

 animal being thus prepared, the web was brought under the microscope and 

 the circulation examined. (/) The part of the circulation to be observed 

 was so selected as to include a good view of an artery, a vein, and the 

 smaller intermediate capillary vessels, (ff) "When the natural condition 

 of the circulation was well observed the chamber was closed by the sliding 

 cover, and through it the narcotic vapour, the effect of which upon the 

 circulation was to be investigated, was gently passed. The vapour was driven 

 over with hand-beUows from a small Junker's apparatus, manufactured by 

 Messrs. Krohne and Sesemann*. By counting the strokes of the bellows it 

 was possible to maintain the same current of vapour at all times. (7i) And 

 lastly, the web was sustained in the same condition of moisture, so as to pre- 

 vent errors of observation due to evaporation from the tissues. 



Such were the precautions taken ; and I am inclined to think they were 

 sufficient, although it will be a great satisfaction to me and an aid in my future 

 labours to hear of any amendments or additions that may be suggested. 

 The narcotic vapours used in the research were hydramyle, chloroform, bi- 

 chloride of methylene, and absolute ether. In some particulars these acted 

 precisely in a similar way, in other particulars they acted in a way more or 

 less peculiar to themselves. 



The first fact I would notice as common to the action of all the vapours 

 used is, that no obvious change in the physical characters of the blood-cor- 

 puscles, red or white, was ever observable ; neither was there any noticeable 

 difference in tlie relationships of the red and white corpuscles to each other. 

 The red corpuscles held their ways so long as there was motion in the centre 

 of the blood-streams, while the white ones rolled along by the sides of vessels 

 in the same manner as they did before the narcotism. 



Another fact common to the action of all the vapours used was, that the 

 first sign of arrested movement of the circulation commenced in every case 

 on the venous side of the circulation, and consisted of a sort of pulsation or 

 to-and-fro movement of the current through the vein ; soon upon this the 

 venous current became obviously slower and the vein dilated, while the 

 arterial current remained, often for a long time, unchanged. 



In every case the minute circulation remained long iu force after the 

 respiration had entirely ceased, and after all evidence of the continuance of 

 life had entirely ceased. On the average the animals ceased to breathe for 

 one hour and thirty minutes after the deep narcotism had set in ; yet all the 

 while the minute circulation was still playing with more or less of efficiency, 

 and so long as it continued the chances of recovery were nearly certain. The 

 cessation of the minute circulation was, on the other hand, the sign and proof 

 of irrevocable death. 



There was still another effect common to all the narcotics used. The cir- 

 culation through the capillaries often stopped altogether, and for considerable 

 intervals of time, when the reduction of the circulatory power was greatest. 

 Under this condition the circulation, such as it was, was maintained by the 

 arteries, in which the blood moved to and fro with occasional slow steady 



* Dr. Ricbardson here fitted up the apparatus, including small chamber, hand-bellows, 

 and Junker'8 bottle, and showed the method by which it was worked. 



