22 Proceedings of the Royal Physical Society. 



applied to Mr Mackenzie to assist us in remedying this 

 deficiency, and lie has very kindly done so by sending both 

 a full-grown living beaver, and a foetus taken from the 

 mother before birth. In sending a living specimen, Mr Mac- 

 kenzie remarked that it would probably ultimately answer the 

 purpose of a skeleton, should the climate of Edinburgh not 

 agree with the animal's constitution. I had destined it for 

 the pond in the Edinburgh Royal Botanic Gardens, where 

 Professor Balfour could have given those interested in natural 

 history an opportunity of studying its habits at their leisure. 

 It might easily have been kept alive if it once had reached the 

 gardens. There would have been no difficulty in supplying it 

 with birch twigs and branches, its native and proper food ; 

 and Mr Mackenzie informs me that it is by no means par- 

 ticular in its food, and that if it had the run of the kitchen 

 (that is, I presume, the opportunity of selecting what it chose 

 from the debris of an ordinary family's table) it would do 

 very well. Unfortunately, it never got the chance of trying 

 the climate of Edinburgh, nor we the chance of trying experi- 

 ments upon it or its food. It reached London alive, but that 

 was all. It died next morning. It was, however, carefully 

 transmitted to me, and along with the foetus received last year 

 was presented by me to Professor Goodsir, who has under- 

 taken to make a careful dissection of it, and to communicate 

 anything he might think of interest. There are a number 

 of points in the internal anatomy on which information is 

 wanted, such as the castor, and the glands which produce it, and 

 others which might throw light on some disputed (I cannot call 

 them doubtful) points in its economy and habits. For instance, 

 we know from Hearne, that the usually received notion that the 

 animal uses its tail as a trowel to plaster its work, is merely a 

 vulgar prejudice, arising from its flapping it on the ground 

 occasionally, and more particularly when about to plunge 

 into the water. Now an examination of the muscles of the 

 tail might, were it necessary, throw light upon this point. 

 But I imagine that the whole structure and habits of the ani- 

 mal explain the use of the tail sufficiently even without ana- 

 tomical assistance. On examining its external peculiarities we 

 find that its fore paws and feet are short and comparatively 



