PHENOMENA. 11 



internal surface for a few moments to an agent, which, by virtue 

 of its chemical action, might be expected to modify or destroy 

 its vitality, such as solution of chromic acid, chloride of gold, or 

 sulphate of copper. The results were decisive : no stasis was 

 produced by irritation in webs which had been thus treated. 



It has been observed that there is an apparent increase of the 

 white corpuscles in the inflamed part, and a remarkable disposi- 

 tion in them to adhere to the walls of the vessel; but as no 

 pores are visible in the capillaries under the highest magnifying 

 powers, the fact that the white corpuscles passed through the 

 vessels into the tissues, which was pointed out by Dr. Addison, 

 and which has now been proved, could not be accepted ; but in 

 1846 the statements of Dr. Addison were confirmed by Dr. 

 Augustus Waller, who says {Philosophical Magazine, vol. xxix., 

 p. 397, 1846), " In some instances the manner in which the cor- 

 puscle escaped from the interior of the tube could be distinctly 

 followed ; that part of the tube in contact with the external side 

 of the corpuscle gradually disappeared, and at nearly the same 

 time might be seen the formation of a distinct line of demarca- 

 tion between the inner segment of the corpuscle and the fluid 

 parts of the blood in contact with it. Any slight agitation then 

 was capable of disengaging the corpuscle from the vessel to 

 which it was now external." The escape of the corpuscle was 

 supposed by Dr. Waller to be due to an exudate being given 

 off from the corpuscle possessing some solvent power over the 

 vessel, or that the solution of the vessel took place in virtue of 

 some of those molecular actions which arise from the contact of 

 two bodies ; actions which are known as exerting such extensive 

 influence in digestion, and referable to what is termed the 

 catalytic power. But it is now proved that the capillaries 

 consist of protoplasm, hence the penetration of their contractile 

 walls by the amoeboid corpuscles, and the subsequent closure 

 of the openings when the passage is completed, can be readily 

 understood. 



In order to do this it must be further borne in mind, as 

 pointed out by Prof. Cohnheim, that a white corpuscle — leuco- 

 cyte, sarcophyte — is not a cell in the sense in which the term 

 was formerly used, but is a mass of contractile material en- 

 dowed with the faculty of movement. This movement, from 

 its similarity to that possessed by the amoebse, has been termed 



