OF THE VENOM OF THE RATTLESNAKE. 19 



relax its hold, until fate or mischance dislodge the now fatallj-armed tooth which 

 it animates." 



Before leaving this portion of the subject, it is proper to state that the views 

 expressed by my friend Dr. Johnston, as to the want of direct continuity between 

 the duct of the poison gland and the tooth canal, have been recently advocated by 

 Prof Jeifries Wyman, of Boston. It gives me great pleasure to point out this 

 coincidence of opinion ; and while acknowledging Prof. Wyman's priority of claim 

 as established by publication, I must not omit to add that Dr. Johnston's manu- 

 script notes — which I have quoted above — bear the date of Oct. 3d, 1859, since 

 which time they have been in my own possession.^ 



The accompanying diagram, Fig. ]0, illustrates our views as to the direction 

 taken by the new fang, in its progress towards the alveolar socket. 



It will have been observed that Dr. Johnston states, that the first reserve fang 

 enters the semilunar socket in the maxilla, to the inside of the active fang. Al- 

 though this is often or usually the case, it is not uncommon to find the two fixed 



Fiff. 10. 





a, Alveolar socket ; b, functionary fang ; c, its successor ; d, the nest fang in order of age ; e, remaining germs. 



fangs, unsymmetrically placed, one on the inner, the other on the outer side, of 

 their respective alveolre, or both on the inner side; or again, both on the outer 

 side of the said socket. 



In all other points, my own researches agree with those of Dr. Johnston. 



May 16th, 1860; Proc. Boston Nat. Hist. Soc. 



