136 Preternatural Growth of Incisors in Mamm, rodentia. 



of the tooth in the lower jaw that led to the disease ; because, 

 under any other circumstances, it seems probable that both 

 pairs of incisors would have been equally elongated; where- 

 as the upper pair were, comparatively speaking, but little 

 affected. In the second rabbit that occurred this was 

 found to be the case, and both pairs were observed to have 

 very much exceeded the usual length ; but then, in this 

 instance, there was such an irregularity in their mode of 

 growth, that we may, perhaps, find a better explanation of the 

 anomaly in some derangement of the jaws, the result either of 

 natural constitution or of accidental injury. Whatever this 

 might have been (for I regret that this rabbit was not pre- 

 served, and no examination of the jaws made at the time), the 

 effect was that of causing the lower pair of incisors, when 

 viewed together, to assume the shape and appearance of the 

 letter V, diverging from one another at the surface of the 

 gum, and extending in opposite directions, to the length of 

 nearly an inch and a half. The degree of divergency observed 

 in the upper pair was nearly as great as this in the lower, and 

 their length about the same ; but their curvature very much 

 greater ; as, indeed, would necessarily result from the greater 

 bend of that portion of the jaw in which these incisors are 

 formed. In this instance, the portion without the gums had 

 completed three parts of an exact circle, and their cutting 

 edges were in close contact with the roof of the mouth. 



Both the above rabbits, when taken, exhibited the appear- 

 ance of being nearly starved to death, through an inabiUty of 

 procuring their usual food. In the first case, life had been 

 sustained solely by the small quantity of herbage which the 

 animal, was enabled to crop with its lips at the side of the 

 mouth, which appeared to have been used for that purpose. 

 In the second instance, even this method of feeding could 

 scarcely have been resorted to with success, the rabbit being 

 absolutely unable to close its mouth, from the pressure of the 

 lower portion of the curve, formed by the upper incisors upon 

 the surface of the tongue. 



The individuals to which the foregoing observations relate 

 occurred in the neighbourhood of Cambridge. I have since 

 then being favoured by a friend with a third example of this 

 monstrosity, in a rabbit killed in Lincolnshire, one of whose 

 upper incisors was even longer than in the case last mentioned, 

 having actually grown into the palate, and reentered that 

 portion of the jaw from whence it originally sprung. This 

 appeared to be the result of some local disease, affecting, in 

 the first instance, that single tooth, which was also much 

 twisted in its direction ; but, as in process of time the growth 

 of this tooth became so great as to interrupt the operation of 



