COMPOSITION OF BLOOD IN DISEASE. 301 



fevers ; the quantity being sometimes as little as 0-9. If any decided 

 Inflammation should develope itself, however, in the course of the Fever, 

 the proportion of Fibrine rises accordingly. A deficiency of Fibrine in 

 the blood predisposes to Haemorrhages, Congestions, &c., either into 

 the substance of the tissues, or on the surface of membranes ; and these 

 conditions are well known to be of frequent occurrence as complications 

 of febrile disorders. An excess of Fibrine is not much affected by 

 copious bleeding, even if this be frequently repeated; but there is 

 reason to think, that the administration of Mercury has a tendency to 

 restrain its production. 



532. It is difficult to say what amount of Red Corpuscles should be 

 regarded as excessive ; since, as we have seen, they may augment to a 

 great degree,, without disturbing the health. When they are present 

 in an amount much above the average, they seem concerned in pro- 

 ducing the condition termed Plethora; which marks a "high condi- 

 tion" of the system, and which borders upon various diseases, espe- 

 cially those of Congestion, and Haemorrhages. To these a pe.culiar 

 liability then exists ; because, although the proportion of Fibrine in the 

 blood is not absolutely low, it is low in reference to that of the Red 

 Corpuscles. Plethoric persons do not seem more liable to Inflamma- 

 tion, than are those of weakly constitution. The quantity of the Red 

 Corpuscles is rapidly diminished by frequent bleeding; and hence it is 

 lowered by repeated Haemorrhages. On the other hand, it is speedily 

 restored to its usual standard under the influence of nutritious diet, if 

 the digestive powers have not been too much weakened to make use of 

 this. The proportion of Red Corpuscles undergoes a marked diminu- 

 tion in various forms of Anaemia ; and particularly in Chlorosis. In 

 severe cases of this latter disease, it has been found as low as 27 in 

 1000 ; and it not unfrequently sinks to 40 or 50. The marked influ- 

 ence of the administration of Iron, in favouring the reproduction of 

 Red Corpuscles, has been already noticed ( 219). 



533. The proportion of Albumen in the blood seems less liable to 

 change, except in the condition termed Albuminuria, in which a large 

 quantity of Albumen appears in the Urine. When this condition is 

 permanently established, it is* indicative of the existence of serious 

 organic disease of the kidney ; but it may occur for a short time under 

 the influence of simple congestion of that organ, which causes an 

 escape of the Albuminous part of the blood, together with the water 

 which is filtered off (as it were) in this gland ( 728). Now ^ when 

 Albuminuria is fully established, there is a marked diminution in the 

 quantity of Albumen in the serum of the blood ; and this diminution 

 is constantly proportional to the amount of Albumen present in the 

 Urine. The proportion of Saline matter appears to undergo less alter- 

 ation in disease, than that of the other constituents of the Blood ; and 

 has not been found to have a regular correspondence, either in the way 

 of excess or diminution, with any particular morbid state. 



534. The condition of the Blood may be affected, not merely by 

 alteration in the proportions of its normal ingredients, but by the pre- 

 sence of other substances ; either such as are generated in it, and are 

 constantly being eliminated from it in health, but have accumulated to 



