BUFFY COAT. PATHOLOGICAL CHANGES IN THE BLOOD. 535 



Blood contains an excessive quantity of Fibrine. it coagulates slowly; thus 

 the blood of a patient labouring under Rheumatism coagulates more slowly 

 than that of one affected with Typhoid fever. The increase may occur in 

 two ways ; either by an absolute increase in the Fibrine, the amount of the 

 corpuscles remaining unchanged, of not being augmented in the same pro- 

 portion ; or by a diminution of the Corpuscles, the quantity of Fibrine re- 

 maining the same, or not diminishing in the same proportion. Hence in 

 severe Chlorosis, in which the latter condition is strongly developed, the buffy 

 coat may be as well marked, as in the severest Inflammation. Unless the 

 composition of the blood be altered in one of these two ways, it is stated by 

 Andral that the bufly coat is never formed; the influence of circumstances 

 which favour it, not being sufficient to produce it when acting alone. The 

 absence of these circumstances may prevent it, however, when it would other- 

 wise have been formed; thus, when the Blood flows slowly, the buff is not 

 properly produced; because the slow discharge gives one portion time to 

 coagulate before another; and only the blood last drawn furnishes the Fibrine 

 at the upper part of the vessel. Again, in a deep narrow vessel, the bufT will 

 form much more decidedly than in a broad shallow one ; because the thick- 

 ness of the Fibrinous crust will be greater. 



6 



6. Pathological Changes in the Blood. 



706. From the part which the Blood performs in the ordinary processes of 

 Nutrition, it cannot be doubted that it undergoes important alterations, when 

 these processes take place in an abnormal manner. These alterations must 

 be sometimes the causes, and sometimes the effects, of the morbid phenomena, 

 which constitute what we term the Disease. Thus, when some local cause, 

 affecting the solid tissues of a certain part of the body, produces Inflammation 

 in them, their normal relation to the blood is altered ; the consequence is, that 

 the Blood, in passing through them, undergoes a different set of changes from 

 those for which it is originally adapted ; and thus its own character under- 

 goes an alteration, which soon becomes evident throughout the whole mass of 

 the circulating fluid, and is, in its turn, the cause of morbid phenomena in 

 remote parts of the system. On the other hand, the strong analogy between 

 many Constitutional diseases, and the effects of poisonous agents introduced 

 into the Blood, appears clearly to point to the inference, that these diseases 

 are due to the action of some morbific matter, which has been directly intro- 

 duced into the current of the circulating fluid, and which has affected both its 

 physical and its vital properties.* Here, then, is a wide field for investiga- 

 tion, of which the surface can scarcely be said to be yet broken up, and 

 which must yield an abundant harvest to those who shall cultivate it with in- 

 telligence and zeal. The first and most complete series of connected re- 

 searches, which have been yet published, on the changes which the blood un- 

 dergoes in disease, are those of MM. Andral and Gavarret ;t these are confined 



: This doctrine has been brought prominently forward, in a paper on Symmetrical Dis- 

 eases, read by Dr. William Buck! before the Medico-Chirurgical Society, Dec. 16, 1841. The 

 Author ingeniously proves, that the symmetry of many diseases (such as certain forms of 

 cutaneous eruptions, rheumatism, &c.) which do not immediately depend upon external 

 causes, necessarily involves the idea of the conveyance of the morbific agent in the circulating 

 fluid ; the palsy produced by lead is a very interesting example, in which the agent is known 

 to be mingled with the blood, and to be deposited in the parts affected, which are generally, 

 if not always, symmetrical. 



I An account of these inquiries will be found in the Provincial Medical and Surgical 

 Journal for May, June, and July 1841; in the Annales des Sciences Naturelles, Dec. 1840, 

 and March 1841 ; and in the Ann. de Chimie, torn. Ixxv. They have since been published 



