242 BLOOD. 



usual, except during the first ten days of typhus, during cholera, 

 and scarlatina and measles in their first stages ; although not unfre- 

 quently we find the serum denser and richer in solid constituents 

 than the normal fluid, or at all events, as dense and rich. Hence, it 

 must be concluded that, immediately after the primary invasion of 

 certain diseases, the blood-corpuscles are destroyed in large num- 

 bers, or at all events are not renewed in sufficient quantities, and 

 that their products of metamorphosis are retained for some time in 

 the serum, and thus increase its solid constituents, or at all events 

 balance its loss. In the further course of acute diseases (with the 

 exception of cholera), the solid constituents of the serum are 

 always diminished, and its specific gravity falls more or less below 

 the normal standard. The only exceptions to this rule occur in 

 the case of acute articular rheumatism, erysipelas, and puerperal 

 peritonitis ; in these diseases there is an extraordinary diminution 

 of the blood-corpuscles, so that the whole blood assumes an 

 abnormally watery appearance, while the serum is denser and con- 

 tains more solid constituents than in the normal state. 



There are certain chronic conditions to which we have applied 

 the names of anaemia and hydrcemia, and which are consequences of 

 severe acute diseases, and especially of such as are associated with 

 considerable losses of the juices, colliquative discharges, or tho- 

 roughly destroyed nutrition. The ideas which we are in the habit 

 of connecting with these names are often not sufficiently distinctive. 

 We are accustomed to associate the form of disease which we 

 name chlorosis with both these states, and especially with anaemia. 

 But if, by the term anaemia, we understand an absolute diminution 

 of the blood and of its solid constituents, chlorosis does not fall 

 within the conditions of anaemia ; and independently of pathological 

 grounds, the chemical composition of the blood is opposed to this 

 view, for in chlorosis, neither the \vhole volume of the blood nor 

 the amount of solid constituents in the serum is diminished, but 

 only the number of the blood-corpuscles. Becquerel and Rodier* 

 have recently examined the serum with much care in various 

 diseases, and have found that the serum of chlorotic patients pre- 

 sents a perfectly normal constitution. If plethora actually depended 

 on an absolute increase of the blood circulating in the vessels, the 

 not very unfrequent occurrence of plethora in chlorosis would also 

 stand opposed to our attaching identical ideas to the terms 

 chlorosis and anaemia. There is no scientifically accurate proof 

 that there is an actual diminution of the whole mass of the blood, 

 * Gaz. de Paris. No. 33 et 36, 1846. 



