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neglect of su])plyiiig to the air a sufficient ąuantity of simple and 

 innoxious moisture is attended with two evils. Not only are the 

 animals kept iu an atmosphere too dry for their healthy preserva- 

 tion ; but the dry air, greedily absorbing moisture, becomes impreg- 

 nated \vith the excreted Hiiids of the animals in confinement ; and 

 thus the secretiug surfaces of the lungs are at once exposed to a 

 constant stimulus from increased and ra])id exhalation, and to the 

 additional stimulus intlicted by the continual breathing of air loaded 

 with saline and irritating particles. In well-constructed houses it 

 is of the first importance that the fluids of the animals should be 

 conducted from the buildings. Ventilation should also be perfect 

 not only through the body of the building, but through each indivi- 

 dual cage or den. This is doul)ly necessary w'here the air is viti- 

 aled, not only by the animals themselves, but by numerous visitors. 

 For the general regulation of tlie admission of cold air a convenient 

 plan is to have a leaden or iron weight balanced i n a vessel of mer- 

 cury, attached to a sliding sash, which \vill thus rise or fall in 

 proportion to the heiglit of the mercury. Mr. Cox regards it as of 

 no importance, as to the effect produced on the atmosphere, by 

 vhat means an increased temperature is preserved, \vhether by flues 

 or steam or hot \vater, if the degree obtained be the šame : the 

 only reason for preferring one to another is the greater facility it 

 may afford of keeping up an eąuable temperature. 



Mr. Owen read a portion of his notes made at the dissection of 

 the Beaver which died lately at the Society's Gardens. He limited 

 himself on this occasion to the description of the organs connected 

 ■with digestion. The salivary organs and those of deglutition were 

 treated of in detail : the former parts, which are remarkahly deve- 

 loped in all the Glires, were especially examined on account of the 

 peculiar nature of the animal's food ; \vhile the latter claimed par- 

 ticular attention from the recent interesting discovery by Mr. Mor- 

 gan of a peculiar construction of the fauces in the Capybura, and 

 some others of the Ilodent order. 



Of the salivarj' glands the parotid are the largest. They are 

 united, likę tlie lateral lobes of the thyroid gland in man, by an 

 anterior transverse portion ; and form together a conglomerate 

 mass \vhich extends across the front of the neck to within a short 

 distance of the upper part of the sternum, covering the larynx and 

 its museles, and passing back\vards on each side as far as the mas- 

 toid process. There are, however, t\vo ducts, one on each side, 

 which terminate in front of the molar teeth. The suhmaxillary glands 

 are quite distinct from the parotid, and are each about the size of a 

 walnut : their ducts pass under the ja\v and terminate at the side of 

 t\ie fr<enum linguce. The sublingual glands are very small. 



Bet\veen the membrane of the palate and the boue, in the narrow 

 space bet\veen the ro\vs of molar teeth, a layer of mucous glands is 

 situated : and a thick stratum of the šame kind of glands exists also 

 immediately exterior to the membrane of the fauces. 



The soft palate extends backwards from the posterior edge of the 



