ITS VITAL PROPERTIES, AND RELATIONS TO LIVING ORGANISM. 203 



in the want of circumscription of collections of pus within an abscess, allowing 

 its infiltration through tissues that were previously healthy, and thus occasion- 

 ing a wide-spread destruction of organized texture, which is characteristic of 

 certain forms of inflammation (this result being usually attributable either to 

 the previously unhealthy condition of the system, or to the introduction of some 

 specific poison into the blood) ; in the want of a corresponding limitation be- 

 tween the living and the dead parts in gangrene, so that hemorrhage takes place 

 on the separation of the slough, the vessels not having been previously obstructed 

 by coagula; and in the entire absence of any effort, either by simple adhesion, 

 or by the formation of connective tissue, whereby the sides of open wounds 

 may be kept together, and dissevered parts brought again into connection. (See 

 CHAP. xi. SECT. 2.) On the other hand, we see the consequences of excess of 

 the proportion of fibrin, and of that increased plasticity (or tendency to fibril- 

 late) which usually accompanies its augmentation, in the tendency to form those 

 plastic effusions which are characteristic of the Inflammatory state, and which, 

 if poured out upon serous or mucous surfaces, constitute " false membranes" 

 and " adhesions," or, if infiltrated into the substance of living tissues, occasion 

 their consolidation. This increased plasticity of the blood, however, may fre- 

 quently be regarded in the light of an " effort of Nature," to antagonize the 

 evil consequences of that depression or positive destruction of the vitality of 

 the solid tissues which seems to form an essential part of the inflammatory 

 condition ; and thus it is that, whilst the central part of a mass of tissue, in 

 which the inflammation has been most intense, suffers complete death, and is 

 carried away in the suppurative process, the peripheral part, in which the vio- 

 lence of the inflammation has been less, becomes infiltrated with plastic matter 

 poured out from the blood, and forms the solid and impermeable wall of the 

 abscess. (See CHAP. xi. SECT. 3.) 



194. Turning now to the Corpuscles of the Blood, we have to inquire into their 

 special functions, and into the nature of their participation in the vital opera- 

 tions of the system at large. Here, also, we are obliged to rely upon evidence 

 of a far less satisfactory nature than could be desired; and at whatever con- 

 clusions we may arrive, we must hold them as probable only, and as liable to be 

 modified by further inquiry. In the first place, upon looking to the chemical 

 constitution of the Red Corpuscles, we have seen that it possesses a remarkable 

 correspondence with that of Muscle, in the proportion of the potash-salts which 

 they contain ; in this respect differing in a very marked manner from the liquor 

 sanguinis. So, again, it exhibits a like correspondence with that of the Nerve- 

 substance, in the quantity of phosphorized fat which it includes ( 142). Again, 

 the peculiar color which the vesicular nervous matter and the muscular substance 

 of warm-blooded animals exhibit, although doubtless attributable in part to the 

 actual presence of red blood in these tissues, yet partly depends upon a pigment- 

 ary matter in their own substance, which seems closely to resemble haematin 

 ( 31). Thus, then, from the relative composition of the Red corpuscles and 

 of the Muscular and Nervous tissues, there appears to be much reason for re- 

 garding the former as destined to prepare or elaborate materials which are to be 

 subservient to the nutrition of the latter. Again, we have seen that, although 

 the difference in the color of the red corpuscles of arterial and venous blood 

 cannot now be considered (as it formerly was) to be an indication of chemical 

 change in their contents effected, on the one hand, by the agency of carbonic 

 acid, and, on the other, by that of oxygen yet there still appears reason to 

 regard these corpuscles as having more power of absorbing those gases than is 

 possessed by any other constituent of the blood ( 142). Hence we may look 

 upon them as specially subservient to the vital activity of the nervo-muscular 

 apparatus ; since it is one of the most important conditions of that activity, that 

 these tissues shall be supplied with duly oxygenated blood, and that the car- 



