DIFFERENT VARIETIES OF METASTATIC DEPOSITS. 



fast where a division of the vessel takes place (Fig. 72, E), 

 because the diverging vessels are too small to admit it. 

 In the case of very large fragments even 

 the principal trunks of the pulmonary Fia 72> 



artery are blocked up, and instantaneous 

 asphyxia ensues ; other fragments again 

 penetrate into the most minute arteries 

 and there give rise to very minute, and 

 sometimes miliary inflammations of the 

 parenchyma. In explanation of these 

 small and often very numerous deposits, 

 I must mention a conjecture which only 

 occurred to me whilst engaged in my more recent 

 observations, but which I do not scruple to declare to be 

 a necessary inference. I believe namely that, when a 

 considerable fragment of a thrombus becomes wedged at 

 a certain point in an artery, it may in its turn crumble 

 away through the onward pressure of the blood, and thus 

 the minute particles to which this crumbling of the lar- 

 ger plug gives rise be conveyed into the small branches 

 into which the vessel breaks up. Thus alone does it 

 seem to me that the fact can be explained, that in the 

 district supplied by an artery of considerable size a num- 

 ber of little deposits of the same sort are often ipund. 



This whole series of cases has nothing whatever to do 

 with the question, whether there is pus in the blood or 1 

 not. We have in them to deal with bodies of quite a 

 different nature, with fragments of coagula in a more or 

 less altered condition, and according as this alteration 

 has assumed this or that character, the nature of the pro- 

 Fig. 72. Embolia of the pulmonary artery. P. Moderately large branch of the 

 pulmonary artery. E. The embolus, astride upon the angle (spur Sporn), formed 

 by the division of the artery. <, t'. The capsulating (secondary) thrombus : t, the 

 portion in front of the embolus reaching to the next highest collateral vessel e; 

 t', the portion behind the embolus, in a great measure filling up the diverging 

 branches r, r\ and ultimately terminating in the form of a cone. 



16 



