VOL. XXXVIII.] PHILOSOPHICAL TRANSACTIONS. 6'25 



are very thin, so that this second part will scarcely bear being distended 

 with wind. 



In a full grown beaver the caecum, which is in form of a sickle, is 18 inches 

 long on the hollow side, and 30 inches on the round side, and 4 inches broad 

 at the larger end, and will contain between 5 and 6 pints of water. In de- 

 scribing the receptacles of the castor, he says, that the uppermost bags contain a 

 soft resinous matter, but that the lower ones are filled with an oily matter ; the 

 greatest bags weigh but 2 oz. 



Dr. Sarrasin says, that he was never able to discover what use this castor was 

 of to the beavers themselves, being well assured that they do not themselves 

 swallow it to excite their own appetite. It is likewise false, that the hunters 

 use it as a bait to draw the beavers into their toils, though they do use it to 

 entice those animals which infest the beavers, as martins, foxes, bears, &c. 



As to their manner of living; they choose a low level ground, watered with 

 a small rivulet, that it may be easily overflowed, which they do by making 

 dams across it: they make these dams by thrusting down stakes of 5 or 6 feet 

 long, and as thick as one's arm, pretty deep into the ground ; these they will 

 wattle across with tender pliable boughs, and fill up the spaces with clay, 

 making a slope on the side against which the water presses, but leaving the 

 other perpendicular. They make their houses after the same manner; the walls 

 are upright, 2 feet thick, and at top in form of a doom : they are usually oval, 

 5 or 6 feet long on the inside, and near as broad, being sufficient to lodge 8 

 or 10 beavers, and 2 or 3 stories high, which they inhabit as the water rises 

 or falls. 



Sometimes they build several houses near together, which communicate with 

 one another. He says there are some beavers called terriers, which burrow in 

 the earth; they begin their hole at such a depth under water as they know that 

 the water will not freeze so deep; this they carry on for 5 or 6 feet, and but 

 just large enough for them to creep through ; then they make a bathing-place 

 3 or 4 feet every way ; from whence they continue the burrow, always ascend- 

 ing by stories, that they may lodge dry as the waters rise : some of these bur- 

 rows have been found to be 100 feet long. They cover the places where 

 they lie with weeds ; and in winter they make chips of wood, which serve them 

 for matelases: they live on herbs, fruits, and roots in summer; but against 

 winter they lay up a provision of wood, a stack of 23 or 30 feet square, and 8 

 or 10 high, is the usual quantity for 8 or 10 beavers: they only eat those pieces 

 which are soaked in the water. Marius says, they only live on such ve- 

 getable food; but his commentator Francus says. Sect. 4, that they prey upon 



VOL. VII. 4 L 



