INFLAMMATION WITHOUT CIRCULATION. 441 



opposite side. It is evident, then, that congestion is not in- 

 flammation, and does not cause it even when long continued. 

 That inflammation can take pLace without congestion, is shown 

 not only by the fact that it occurs in non-vascular tissues, such 

 as the cornea and cartilage, but even more strikingly by the 

 remarkable observation of my friend Dr. Ainslie Hollis, tliat 

 textural changes similar to those produced by inflammation in 

 higher animals, follow the application of irritants to anemones 

 which have no vascular system whatever.* The tw^o processes 

 of congestion and inflammation are therefore quite different, and 

 each can exist independently of the other. JSTe vertheless, con- 

 gestion accompanies inflammation in the great majority of cases, 

 and modifies its progress. While we carefully bear in mind 

 that the two processes are not identical, let us now try to see 

 wh?*.t the connection is between them, and in doin^r this, let us 

 begin by inquiring how congestion is produced. From Dr. Stir- 

 ling's experiment, it is evident that a copious supply of blood is 

 beneficial to the tissues, and that if all the vessels throughout 

 the body were dilated, and blood flowing freely through them, 

 the tissues in general would be much better off than they are. 

 But in order to have these dilated vessels sufficiently full, the 

 body would require twice as much blood as it has ; to supply 

 the blood, the digestive organs would need to be larger, and tlie 

 heart must be more powerful in order to propel it ; in short, 

 the individual w^ould require to be re-made on a different plan.' 

 The arrangement, which has been found by experiment to exist 

 in animals, is much more economical. The quantity of blood 

 in the vessels is not sufficient to fill them even half full if they 

 were all dilated at once,t but by means of the vaso-motor nerves 

 which have their centre in the medulla oblongata and spinal 

 cord, they are kept in a state of semi-contraction sufficient to 

 enable the blood to fill them. Whenever the vaso-motor nerves 

 are divided, the vessels they supply become dilated, so as to 

 offer little or no resistance to the flow of blood, and the current 

 through them consequently becomes rapid. Thus in the rabbit 



* St. Sartholomeiv's Hospital Reports, 1874, p. 2G7. Journal of Anatomy 

 and Fhusiology, voL vi, p. 386 ; vii, p. 80 ; and viii, p. 124. 

 t Schiif, Lo Sperimendale, 1872, p. 369. 



