216 REPORT — 1860. 



means of two grooved wheels, the edges are pressed together, and thus the wire 

 becomes encased in a perfect tube of india-rubber. As many additional tubes as 

 may be desired can be then put on. The machine is also applicable to the coat- 

 ing of wires with what is Known as Wray's Compound, with vulcanized India- 

 rubber and other compound substances containing India-rubber. 



APPENDIX. 



Physiology. 



On the Deglutition of Alimentary Fluids. 

 By Professor J. H. Corbett, M.D. 



In this paper the author describes two distinct forms of deglutition ; that while the 

 alimentary bolus is propelled with rapidity over the epiglottis, fluids can flow in 

 two streams, one at each side of the epiglottis and of the aryteno-epiglottic folds, 

 without the danger incidental to its passage over the central aperture of the larynx. 

 lie believes that such occurs in the newly-born infant and mammal during suction ; 

 it can take place in the sipping of fluids, swallowing of the saliva, and even during 

 drinking in a continuous draught. Ordinary drinking is accomplished by gentle 

 muscular movements, which should not be confounded with the gulping of fluids. 

 In gulping, the fluid is rapidly and forcibly propelled backwards through the 

 isthmus of the fauces, each gulp requiring a separate act of deglutition ; such act 

 much resembles the deglutition of solids. The author contends that when the infant 

 or mammal seizing and retaining the nipple, sucks in the fluid in an almost con- 

 tinuous stream, the process of respiration is not totally interrupted, as should 

 occur if the fluid absolutely passed in the middle line over the epiglottis ; it is 

 argued that the salivary secretion is swallowed safely during sleep ; fluid carefully 

 introduced into the mouth of persons in a state of insensibility, passes into the 

 pharynx ; fluid poured geutly into the mouth of a patient whose head rests upon 

 one side, flows backwards by a gentle act of deglutition, which is chiefly performed 

 in this instance by the muscles of the corresponding side ; fluids cannot be shaped 

 like solid food into a definite form ; alimentary drinks must be subject, in their course, 

 to the laws which regidate the passage of fluids in other cases ; the root of the 

 tongue being narrow and the organ convex on its upper surface, fluids must naturally 

 have a tendency to flow from the middle line to either side ; during the mastication 

 of solid aliment, the juices expressed by the action of the teeth aud pressure of the 

 tongue, rapidly escape backwards, so that the bulk of the mass is considerably 

 diminished before the deglutition of the solid part is attempted ; during inflam- 

 matory affections of the tonsillitic glands, the swallowing of fluids is attended with 

 difficulty, while a moderately sized portion of solid aliment, which proceeds in 

 the middle line, may be transmitted with comparative facility ; when a single 

 gland is much inflamed, deglutition is chiefly performed at the opposite side. 



In experiments made by the author on the dead body, fluid poured upon the 

 dorsum of the tongue passes backwards into the pharynx in two streams, through the 

 grooved channels situated at each side of the epiglottis and aryteno-epiglottic folds. 



From all these considerations, it is inferred that in the living body, during the 

 deglutition of fluids, the inula falls forward upon the tongue in front of the epi- 

 glottis; thus both uvula and epiglottis afford protection to the respiratory apparatus. 

 The fluid is divided by the uvula into two currents, which descend at each side 

 of the root cf the tongue, under the half arches of the palate, as water flows under 

 the arches of a bridge ; aud such is the principal use of the uvula. The anato- 

 mical arrangements in the human body are perfectly adequate for the transmission 

 of fluid in this safe manner. The anatomy of the porpoise, in which the larynx 

 rises for several inches above the level of the tongue, affords a strong confirmation of 

 this view, which is further sustained by instances in which the epiglottis has been 

 destroyed, wounds of the throat, &c. The distinctness of the two forms of deglu- 

 tition is also indicated by the fact that the mouth may be filled with food, and yet 

 drink can be swallowed without displacement of the solid aliment; the newly-bom 

 infant can perform suction in a perfect manner ; on the other hand, the power of 

 swallowing solid food is gradually acquired, and the organs of deglutition are trained 

 by successive steps to the safe performance of this process, 



