92 LECTURE III. 



especially, to the muscular and nervous, systems. Still, 

 these formations are by no means excluded ; we find 

 pathological new formations of every description, no 

 matter to what tissue they may be analogous, provided it 

 possesses distinctive features. It is only with regard to 

 their frequency and importance that a difference prevails, 

 and this is of such a nature that the great majority of 

 pathological productions contain cells analogous to epi- 

 thelial cells, or to the corpuscles of the connective 

 tissues, and that of those structures which we have 

 included in the last class of normal tissues, the vessels 

 and parts which may be compared with lymph and 

 lymphatic glands are the most frequently met with as 

 new formations, whilst real blood, muscles, and nerves, 

 are the most seldom found as such. 



But, if we ultimately arrive at such a simple view of 

 the matter, the question of course arises, what becomes 

 of the doctrine of the heterology of morbid products, to 

 the upholding of which we have long been accustomed, 

 and to which the most simple reflection almost inevita- 

 bly conducts us. Hereunto I can return no other an- 

 swer than that there is no other kind of heterology in 

 morbid structures than the abnormal manner in which 

 they arise, and that this abnormity consists either in the 

 production of a structure at a point where it has no 

 business, or at a time when it ought not to be produced, 

 or to an extent which is at variance with the typical 

 formation of the body. So then, to speak with greater 

 precision, there is either a Heterotopia, an aberratio loci, 

 or an aberratio temporis, a Heterochronia, or lastly, a 

 mere variation in quantity, Heterometria. But we must 

 be very careful not to connect this kind of heterology in 

 the more extended sense of the word with the notion 

 of malignity. Heterology is a term that, in its histolo- 

 gical meaning may be applied to a large proportion of 



