NUTRITION. 



753 



left at rest. A case has fallen under the writer's 

 observation, in which both limbs were affected 

 with almost complete (hysteric) paraplegia ; 

 but one was also frequently seized with violent 

 cramps, from which the other was free ; the 

 difference in the muscularity of the two limbs 

 was very striking, and was evinced by the 

 greater circumference of the one affected with 

 cramps (which was an inch and a half larger 

 round than the other), as well as by its greater 

 firmness of flesh. Similar facts may be ad- 

 duced, in regard to atrophy of nerves, from 

 interruption of their normal function. Thus 

 when the cornea has been rendered so opaque 

 by accident or disease, that no light can pene- 

 trate to the interior of the eye, the retina and 

 the optic nerve lose, after a time, their charac- 

 teristic structure ; so that scarcely a trace of the 

 peculiar globules of the former, or of the nerve- 

 tubes of the latter, can be found in them. 

 These and similar facts are readily understood, 

 when connected by the general principle for- 

 merly laid down, that every proper vital 

 operation involves an act of nutrition ; in such 

 a manner that, whilst the vital properties of any 

 part are dependent upon its due nutrition, the 

 amount of its nutrition will in return depend 

 upon the degree in which these properties are 

 exercised. 



Partial atrophy may depend, however, upon 

 causes of a purely mechanical nature ; such, 

 for example, as produce an interruption of the 

 current of blood through the part. This may 

 result from changes in the arteries supplying it, 

 such as ossification, or other forms of obstruc- 

 tion. Or it may be consequent upon disease 

 in the part itself; as when the deposits produced 

 by inflammation tend to contract, and thus to 

 press upon the vascular structure, which fre- 

 quently happens in the lungs, liver, and 

 kidneys; or when the inflammation occurs in 

 the vessels themselves, causing adhesion of 

 their walls, and obliteration of their tubes; or 

 when a new growth absorbs into itself all the 

 nutritive materials which the blood supplies. 



Abnormal forms of the nutritive process. 

 Under the preceding head we have considered 

 the chief variations in the degree of activity 

 that are witnessed in the ordinary or normal 

 conditions of the nutritive process, that is, 

 those conditions in which the products are 

 adapted by their similarity of character to re- 

 place those which have been removed by dis- 

 integration. But we have now to consider 

 those forms of this process, in which the pro- 

 ducts are abnormal, being different from the 

 tissues they ought to replace. We shall con- 

 fine ourselves to a brief examination of the two 

 most important of these states ; that which is 

 termed inflammation, and that which gives 

 rise to tubercular deposit. The former results 

 from an excess of the plastic element in the 

 blood : the latter from a depraved condition of 

 it, whereby its plasticity is impaired or de- 

 stroyed. 



Notwithstanding all the attention which has 

 been given to the state of the vessels in inflam- 

 mation, a careful consideration of its phenomena, 

 with the light which recent investigations have 



VOL. III. 



thrown upon these, leads us to attach com- 

 paratively little importance to this, and to seek 

 for the essential character of the process else- 

 where. The researches of Addison, Williams, 

 Barry, Gulliver, Andral, and others, all seem 

 to point to the following conclusions. 1. That 

 there is a peculiar afflux or determination of the 

 white corpuscles of the blood towards the in- 

 flamed part. 2. That the total amount of these 

 corpuscles in the circulating blood undergoes 

 a great increase. 3. That the quantity of fibrin 

 in the blood augments in proportion to the ex- 

 tent and intensity of the inflammation ; and 

 this even when it was previously, from the 

 influence of some other morbid condition, 

 below the usual standard. With its quantity, 

 its plasticity or tendency to organization also 

 increases in a healthy subject. Now when 

 these frets are compared together, and are con- 

 nected with those formerly adduced, in regard 

 to the probable function of the white corpuscles 

 of the blood, they lead almost irresistibly to the 

 conclusion, that the process of inflammation 

 essentially consists in an undue stagnation of 

 the white corpuscles of the blood in the vessels 

 of the part, an excessive multiplication of these 

 by the ordinary process of generation, and a con- 

 sequent over-production of fibrin. By these 

 changes, and by the results which follow them, 

 inflammation may be distinguished from the 

 various forms of hyperaemia and congestion. 

 To the results, then, we shall next direct our 

 attention. 



It may be inferred, we think, from various 

 phenomena, that whilst the formative power of 

 the blood is increased in inflammation, that of 

 the tissues is diminished. Certainly this is the 

 case in regard to the system at large, when 

 febrile irritation has been established ; for, not- 

 withstandingthe increased plasticity of theblood, 

 we see the body wasting, instead of increasing in 

 vigour. And it may be inferred, also, in regard 

 to the tissues of the part affected, from the ten- 

 dency to atrophy and disintegration which they 

 exhibit; and which is greater (leading even to the 

 death of whole parts) in proportion as the in- 

 flammation is more intense, and as the tendency 

 to the deposit of new products is the more 

 decided. That a stagnation of blood takes 

 place in the vessels of the inflamed part is 

 another general fact, which throws some light 

 upon the nature of the process ; for this stag- 

 nation is obviously favourable to the transu- 

 dation of the fluid plasma of the blood, through 

 the walls of the vessels, into the surrounding 

 tissue, or upon a neighbouring surface. This 

 deposition of the fibrinous element, possessing a 

 high degree of plasticity, and capable of spon- 

 taneously passing into simple forms of tissue 

 (which may be gradually replaced by higher 

 forms, when penetrated by vessels from the 

 surrounding parts), may be regarded as the 

 first characteristic result of inflammation. That 

 this deposition of the fibrin, which has accu- 

 mulated to an unusual extent in the blood, 

 should take place only in the inflamed part, 

 cannot perhaps be very readily accounted for; 

 but we see that, when the inflammatory 

 diathesis is once established, or, in other 



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