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TRANSACTIONS OF THE SECTIONS. 113 
illustrations were accepted as highly satisfactory; but the theory itself, being 
somewhat novel in relation to physiology, has remained altogether unappreciated 
by the profession. The object of the present paper, therefore, was to bring forward 
a case of similar action occurring zz situ, in connexion with the teeth, which should 
afford a more decisive illustration of the fact of electrolysis having taken place in 
the mouth under corresponding circumstances, and the elements of the tooth sub- 
stance having become so disposed of. The proof tendered was as follows :—On 
removing a ligature of silk twist which had been placed upon some upper front 
teeth, adeep groove was found to have been formed in the enamel along its entire 
course ; at the same time the fibres of the silk had become matted together with 
an incrustation of crystals of lime, showing an unmistakeable case of electrolytic 
transfer, in which the lime-salts of enamel had been dissolved and recrystallized 
upon the sill. 
In the theory of dental decay by electrolysis, particles of charcoal arising from 
eremacausis or slow combustion, which like the silk are electro-negative, are re- 
presented as playing the same part with the enamel and dentine as the silk had 
done in the present instance ; but it was also stated that pressure, rendering the 
part non-homogeneous, was equally capable of producing a negative centre from 
which local galvanic action would arise. The characters peculiar to decayed 
dentine are its entire decalcification and absence of lime solution, but having in 
its stead an abundance of free acid—two features which all other theories are 
incapable of accounting for. Ifa piece of ivory be placed for a few days in water 
under the electrodes of a small sustaining battery, the spot beneath and ‘around the 
anode, or positive electrode, will be found to have become decalcified, softened, and 
strongly acid, just as these conditions occur in natural decay. In addition to this, the 
lime will be transferred to the cathode inthe same manner as it was to the silk, a fact 
which affords the only intelligible explanation of the formation of tartar yet offered, 
Tartar may be thrown down from the saliva as an electro-deposit; it is repelled by 
the electro-positive crown of the tooth, but adheres to the electro-negative root at 
its neck. This polar condition of the tooth, illustrated in the different modes of 
growth between the crown and the root, is referred to as a very important character, 
and one to be well considered ; for all remedial and reparatory measures, to be 
successful, must be in harmony with such an arrangement. 
On the Connexion between Chemical Constitution and Physiological Activity. 
By Dr. A. Crum Brown. 
Is the Eustachian Tube Open or Shut in Swallowing ?* 
By Professor Cretanp, M.D. 
Professor Cleland pointed out that in ordinary circumstances the tube is 
really open, and not shut as was taught by Mr. Toynbee. In support of this state- 
ment he mentioned that he had had the opportunity of seeing the orifice of this 
tube in a patient with a limited ulcer of the palate, and that he had made this 
patient swallow with his mouth open, and had the satisfaction of demonstrating: to 
several pupils that the Eustachian orifice was then momentarily closed. He pro- 
ceeded to take up the anatomical part of the subject, and showed that the disposi- 
tion of the palatal muscles was in harmony with this observation, and such as to 
render Mr. Toynbee’s theory untenable. 
On Flukes from the Indian Elephant. By Dr. Coszoxp, F.R.S. 
The object of this communication was to prove (from specimens forwarded by 
Vet.-Surgeon J. Thacker, through Dr. Cleghorn) that the trematode worms in 
question were referable to the genus Fasciola, constituting a new species, which, 
as such, had never hitherto been properly described. He proposed to name it after 
Dr. Jackson of Boston, U.S.; thus Fusciola Jacksonii, Cobbold= Distomum elephantis 
of Jackson and Diesing. 
Nae ie paper is published in the Journal of Anatomy and Physiology, November 1868. 
58. 8 
