143 



portions of nerve will approximate and finally unite, while the 

 foreign substance which impeded this union i's absorbed in their 

 progress towards this end. It is impossible to develop these 

 mysterious relations: it may however be suggested, either that 

 the precise living principle of the nerve has a power of conversion 

 with respect to that of the intervening texture ; or, that as the 

 former increases by assimilation, it engages, from the superior 

 affinity which may belong to it, as its proper sphere, all the ele- 

 mentary properties which can subserve to assimilation in this seat; 

 thus, of course, compelling the extinction of any other assimilating 

 form of life. This suggestion gives rise to another alternative 

 with respect to the time in which the continuity of the principle 

 of an interrupted nerve (or other structure) is restored, viz. that it 

 is only in a ratio to the increase of the principle from the ex- 

 tremities, and a corresponding or synchronous formation of the 

 structures. 



53. Our plainest inference therefore seems to be, the re- 

 generation of lost parts being limited in its extent; being also 

 subject to much variety, and each view involving some difficulties, 

 uot to say contradictions; that processes occur in growth, which 

 are distinct from mere assimilation and its consequences, or which 

 give additional complexity to this process and these effects. 



54. The subject of organization, or re-production, is one 

 upon which much vanity has been expended. Every one can ex- 

 plain it, and yet no one has even conceived a difficulty belonging 

 to it which would puzzle a mere simpleton. It is amazing how 

 men can flourish, and strut, and talk, and write, pompously and 

 dogmatically, upon subjects about which they know nothing; 

 when at the same time an assumption of knowledge is made the 

 basis of their impudence and importance. But as the world is 

 civil enough to allow men to pass only for what they assume, it is no 

 wonder that those who know the least, should find it necessary to 

 assume the most. Those which are called the doctrines of ad- 

 hesion, re-production, &c. are boasted doctrines; it happens how- 

 ever that they are no doctrines at all, or else the doctrinal parts 

 are of a new and curious kind : union by the first intention, &c. 

 the healing of an ulcer, &c. this is how they are spoken of; a 

 medium of coagulable lymph is thrown out, and vessels shoot into 

 it ; or granulations are thrown out, the ulcer is filled up, and then 

 skins over. I can discover no doctrine here, except it is designated 

 by the words marked in italics, to wit, the throwing of lymph and 

 granulations, and the shooting of vessels; the detail is simply one 

 of sensible effects which are different from doctrines. This detail 

 is short, simple, easily come at, and, above all, for practical uses, 

 highly valuable; but if we would have some doctrines upon the 

 subject, we must consider the throwings and shootings only as short, 

 convenient expressions, and seek deeper for a clue to the explanation. 



55. In conformity with the preceding views (upon which I 

 presume no further than an evidence, at best doubtful, warrants) 



