CHAP. III.] THE BLOOD IN DISEASE. 137 



probability, nearly always dependent upon some modification of the 

 organs which intervene between the external world and itself, of the 

 organs through which certain of its materials have to pass in order to 

 reach it, or of the organs through which other of its materials have to 

 pass before they can be eliminated. 



The progress of biological research has tended more and more to 

 confirm this view of the relation of the blood to the organs of the 

 body, and to transfer the vital processes to those elements of the 

 various organs which we term cells, modified though these may be 

 from the ideal conception of the cell in its primordial condition, as 

 represented, for instance, by the mammalian ovum, or the cells of 

 embryonal connective tissue. 



Apparently, it is in connection with those extra- vascular centres of 

 nutrition, the cells, that take place those chemical processes (nearly 

 all of which are associated with oxidation) which result either in 

 the assimilation of fresh matter for the body's use, or of elimina- 

 tion of waste matter which would accumulate to the body's detri- 

 ment, or which primarily have for their object the evolution of 

 the kinetic energy which the body needs, in order that it shall 

 perform its internal and external work ; so that the life of an 

 organ, as evidenced by its ability to perform those acts which 

 characterize it as alive, may be philosophically considered as the sum 

 of the life of its constituent living centres, the cells, and the life of the 

 organism as, in one sense, the sum of the life of all the constituent 

 living centres of its various organs. 



If this view be correct, disease will, in all probability, depend 

 primarily upon modifications in the processes of cells, rather than of 

 the fluid whence cells obtain their nourishment, and we shall be quite 

 prepared to find (1) that a morbid process may seriously interfere 

 with organs whose functions are essential to life, without influencing 

 the composition of the blood in a manner perceptible by our methods 

 of chemical and microscopic analysis, however delicate these may be, 

 and (2) that when a marked change is revealed by these methods of 

 enquiry it must be a difficult matter to trace the component causes of 

 which the change is the resultant effect. The first proposition is 

 proved by the paucity of results which have been obtained in spite of 

 the assiduous labours of many scientific physicians, the second may be 

 well illustrated by taking as an example that change in the blood which 

 is better characterized than all others, viz. anaemia, or that condition 

 in which the relative and absolute number of the coloured corpuscles 

 of the blood is diminished. 



It is a condition which may result from accidental losses of blood, 

 or from some process (for example, abundant suppuration) which tends 

 unnaturally to drain the blood of some of its constituents, or from a 

 deficiency of proper food, or from causes so complex that we willingly 

 hide our ignorance under the expression of disorders of nutrition. 

 Where the actual fault primarily lies can, in many cases, be not even 

 guessed at, and the physician knows little more than that the disorder 



