164: LECTURE VI. 



blood. There remains in this case, therefore, a quid ig- 

 notum, and you will, I am sure, deem it excusable, if we 

 are unable to say whence a dyscrasia proceeds, of which 

 we are altogether unacquainted with the nature. How- 

 ever, the knowledge of the nature of the change in the 

 blood does not involve an insight into the requisite con- 

 ditions for the dyscrasia, and just as little is the reverse 

 the case. In the case of the haemorrhagic diathesis, also, 

 it must at all events be regarded as an important step in 

 advance, that we are in a number of instances able to 

 point to a definite organ as its source, as, for example, 

 to the spleen or liver. The chief point now is to deter- 

 mine what influence the spleen or the liver exercises 

 upon the special composition of the blood. If we were 

 acquainted with the nature of the changes effected in the 

 blood by the influence of these organs, it might not 

 perhaps be difficult from our knowledge of the dis- 

 eased organ also at once to infer what kind of change 

 the blood would experience. But it is nevertheless an 

 important fact that we have got beyond the mere study 

 of the changes in the blood, and have been able to ascer- 

 tain that there are definite organs in which the dyscrasia 

 has its root. 



In conformity herewith we must conclude that, if 

 there is a syphilitic dyscrasia in which a virulent sub- 

 stance circulates in the blood, this cannot be perma- 

 nently present there, but that its existence must be due 

 to the persistence of local depots (Heerde), whence new 

 quantities of noxious matter are continually being intro- 

 duced into the blood. By following this track we arrive 

 at the conclusion which we have already mentioned, and 

 which is of extreme importance in a practical point of 

 view, that, namely, every permanent change which takes 

 place in the condition of the circulating juices, must be 

 derived from definite points in the body, from individual 



