JAN 17 1901 



7. Description or the Human Spines Showing Nujiekical Variation in the 

 Warren Museum of the Harvard Medical School. 



By Thomas Dwight. 



" Judging whether another proves his position is a widely different thing from proving your own. 

 To establish a general law requires an extensive knowledge of the i^henoniena to be generalized, but to 

 decide whether an alleged general law is established by the evidence assigned merely requires an adequate 

 reasoning faculty. Especially is such a decision easy when the premises <lo not warrant the conclusion.'' 



Herbert Spencee.^ 



This paper is first of all a description of a collection of forty-five anomalous human 

 spines in tlie Warren Museum of the Harvard Medical School, which, with one excejDtion, 

 were obtained by me in the dissecting-room. It represents many years' work. There 

 are not only series representing many grades of certain peculiarities, but some specimens 

 which I believe are unique, and others that are extremely rare. There are two spines 

 with 26 praesacral vertebrae, of which the last is more or less sacralized on one side but 

 certainly a lumbar. Other rare ones are mentioned later. ' These spines are all ligamen- 

 tous preparations; so there can be no suspicion of the hiter- or excalation of a vertebra 

 by the articulator. I have carried the principle of ligamentous preparation to such an 

 extent as to throw aside some good specimens in which the preliminary maceration had 

 unfortunately been excessive. In two or three cases the atlas is lost, and in several the 

 coccyx is more or less incomplete. At least once the sacrum is imperfect. Besides these 

 spines there are several parts of the column, mostly of my collecting, which are described 

 later. Some of the latter are mentioned by way of showing all that is in the collection, 

 but some of them are intrinsically valuable. 



The purpose of this paper is both to discuss what these spines teach concerning the 

 significance of numerical variation of the vertebrae, which opens many important scientific 

 questions, and to make the collection available to others. 



Rosenberg' s System. — The paper which, beyond all doubt, has had the most impor- 

 tant influence on this question is that of Rosenberg (76) , which he has lately supple- 

 mented by another ('99) containing a description of a spine Avith two additional praesacral 

 vertebrae and 15 ribs, of which one pair is cervical. The fundamental idea is that the 



'British and Foreign Medico-Chirurgical Review. Vol. X.Kll. Oct., 1858. 



