394 PROGRESS OF VETERINARY SCIENCE AND ART. 
I shall not translate M. Lafosse’s description of the pro- 
ducts he extracted. They were composed of tooth-substance ; 
and although it has been questioned whether it is real tooth 
that is developed in the shape of accidental growths in the 
vicinity of the ear, still it is now a well-established fact, how- 
ever puzzling to the minds of some it may be to comprehend 
the origin of their existence. 
Lafosse attempts a teratological explanation, but first asks, 
ee If teeth are looked on as arising from the tegumentary 
system, considering them in most animals as emanating from 
papillae and mucous membrane, where was the dermoid 
papilla that constituted the basis of development of this tooth, 
deeply seated and close to the ear, especially as what might 
be taken as the crown looked towards the inner surface of 
the skin?” 
Further on, Lafosse shows that in certain animals teeth 
absolutely emanate from the osseous system, such as in the 
coluber scaber , and other serpents, in which true osseous emi- 
nences, coated by enamel, pierce the oesophagean tunics, and 
project into the tube, whereas they are attached to about 
thirty vertebrae, of which they form the inferior spinous 
process. These are intended to crush the eggs that the 
serpents feed upon. 
Having established that as well as developing from mucous 
membrane, teeth may spring from bone, Lafosse leads us, 
where we-neve^-suspect^d,. to consider the dental tumours, 
above spoken of, as congenital, and he looks on them as having 
sprung from some rudiment of a maxillary bone. In a word, 
he looks on it, without offering-any plausible explanation, 
as a foetal inclusion. “ It cannot,” says Lafosse, ec be looked 
on as an osseous transformation of certain tissues.” 
I have spoken of the case at length, as, surgically, it is of 
the very greatest interest. As pathological anatomists, it is 
most laudable to study the laws that govern disease as well 
as health, and hence most praiseworthy to dive into the 
mysteries of the origin of monsters, so it is even essential to 
adhere to facts, and not sacrifice them to theoretical expla- 
nations. In common with others, I have studied several of 
these dental tumours ; they may spring from several of the 
bones of the head, but especially from the vicinity of the 
petrous temporal bone. They may project towards the in- 
terior of the cranium, more frequently do they extend out- 
wardly. They may be strongly implanted in the bone, or get 
separated, and then they are maintained in their situation by 
the soft textures around. Their developement is not more 
extraordinary than that of other osseous growths that spring 
