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tence, always connected by nervous tissue. While my own work has never yet ied me to investigate, 

 or even to seriously consider, the manner in which the cranial nerves develop, it has Ied me to con- 

 clude, as I have already had occasion to State, that; (I) the relations of the nerves to the skeletal 

 Clements axe so remarkably constant that if the nerve itself does not exist from the very beginning, 

 some tissue or condition of tissue, defining its path, or some markedly strong inherited tendency 

 must certainly so exist; and (2), that whenever a nerve is deflected from its accustomed and apparently 

 predetermined path, carefui examination and consideration will almost always show that it has 

 simply been pushed or puUed one way or the other, surrounded to a difierent extent or in a different 

 manner by the encroaching and enveloping growth of adjacent tissues, or even actually displaced 

 relative to certain tissues or structures by a Variation in the relative time, or in the relative degree 

 of development of the nerve and those other tissues. That there are certain apparently inexplicable 

 exceptions to this rule, I know füll well. 



According to the latter of these two conceptions of the nervous System, the general course 

 of a nerve and its relations to the skeletal and other elements, properly determined, definitely dehne 

 the segmental position of the nerve, and its centers of origin must be in accord with those determ- 

 inations. 



According to the other conception, carried to its legitimate extreme, the course of nerve fibers 

 is not necessarily segmental, and, the terminal distribution of sensory fibers also not being necess- 

 arily segmental, the only positive criterion of the segment or segments to which the component 

 fibers of a certain nerve belong is their points of origin in the central nervous system. Furthermore, 

 the cranial segment to which it is assumed that certain fibers must necessarily belong having been 

 determined by their central origin, the elements of accident, individual experience, or even a sort 

 of elective selection are introduced as natural and constant occurrences to explain the apparently 

 unsegmental peripheral course of certain of those fibers; and where certain sensory fibers are assumed, 

 in the wording of the descriptions, to grow centripetally from certain sense organs to the brain, 

 the same elements of accident, experience or elective selection may determine their peripheral 

 course in one segment and their central origin in another. It is needless to refer to the many 

 expressions and Statements that seem to lead legitimately to these conclusions, and while these 

 Statements definitely impress the reader it is possible that they may not always give correctly 

 the definite opinions of the authors making them. 



These two radically different conceptions of the origin and development of the peripheral nervous 

 System lead, frequently,to totally different interpretations of the facts of distribution, this being especially 

 marked in relation to the branches of the trigemino-facialis complex. Stannius, apparently an advocate 

 of the earlier conception of the nervous system, assigned the fibers of this complex to the trigeminus 

 or facialis nerves according as they issued from the skull by one set of foramina or another, or had a 

 distribution to what he considered as trigeminus or facialis regions ; and he accordingly considered the 

 roots of the complex as partly trigeminus, partly facialis, and partly mixed. Later authors first assigned 

 all the lateralis fibers of the complex to the facialis, irrespective of their course and distribution, and 

 now, still later, recent advocates of the component theory assign all the communis fibers also to that 

 same nerve. I, myself, have accepted and advocated the assigning of the lateralis fibers of the complex 

 to the facialis, but as I am not prepared to accept the assigning of the communis fibers to that nerve, 

 I begin to doubt the justice of so assigning the lateralis ones. This will be further discussed when 

 describing certain of the branches of the complex. To avoid confusion I still adhere to the «nomen- 



