374 CAPILLARY ATTRACTION, ETC. [MEMOIR XXVI. 



the current as seen under the microscope ; the movement 

 in the capillaries after the heart is cut out; the empty 

 condition of the arteries after death ; the phenomena of 

 acardiac monsters; local inflammations and congestions; 

 the gangrene of parts while their capillaries are pervi- 

 ous; the retardation of the current on the application 

 of cold or of carbonic -acid gas; the results of asphyxia 

 and death by drowning or hanging ; the changes of press- 

 ure in the arteries and veins respectively during a check 

 on the respiration ; the vis a tergo of the veins ; the ef- 

 fects of a ligature on those vessels ; the action of irres- 

 pirable gases when breathed, and the opposite condi- 

 tions when oxygen gas or protoxide of nitrogen is used. 

 A doctrine which accounts with simplicity for such a 

 long list of miscellaneous facts commends itself to our 

 attention at once. There are, however, considerations of 

 a still weightier character which must compel us to 

 adopt it. The affinity between the blood and the parts 

 with which it is in contact is a chemical fact beyond 

 contradiction. The pressures and motions I have been 

 speaking of follow as the inevitable consequences of that 

 affinity. We therefore cannot gainsay their existence in 

 the living mechanism, and the only doubt we can enter- 

 tain is as to whether they are of competent power to 

 produce all the effects before us. But after what has 

 already been said respecting the energy of endosmotic 

 movements against pressures of many atmospheres, we 

 may abandon those doubts; and since we have here a 

 force of universality enough and intensity enough, and 

 in every instance acting in the right direction, it would 

 be unphilosophical to look farther, since such a force 

 must, under these conditions, exist in the physical neces- 

 sity of the case. 



