37 



croup, bronchitis, &c. ; and it is well worthy of consideration whether 

 inflammatory affections of the respiratory organs arising from such a 

 cause would not be materially benefited by saturating with moisture 

 the air of the apartments inhabited. Evaporation should during its 

 continuance be promoted in menageries, either by placing wet cloths 

 over the pipes employed for heating them, or by means of a fountain, 

 or by exposing in different parts of the rooms vessels containing 

 water. 



In the preceding observations the preservation of animals brought 

 from tropical climates has been chiefly considered ; but the keeping 

 of those which are obtained from the northern or more elevated re- 

 gions is apparently even more difficult. 



The Rein-deer and the C/zamois scarcely ever continue to live during 

 even a moderate period in our climate, the diti^^erences between which 

 and that of the countries of extreme cold are worthy of especial con- 

 sideration. One of these is the heaviness of our atmosphere, as com- 

 pared with the highly rarefied state in which it exists in elevated re- 

 gions ; a difference so great as to increase the pressure of the air 

 on the human body to the extent of 5500 lbs. beyond that which it 

 sustains at an elevation of 1200 toises. To obviate this, no sugges- 

 tion can be advanced. Another marked distinction is the extreme hu- 

 midity of England during the winter months, a state highly detrimental 

 to life in beings adapted to a dry atmosphere ; for a frosty atmosphere 

 is (as has been before remarked) necessarily a dry one, and at a tem- 

 perature of —20° it is absolutely dry. The effect on animals of so 

 great a contrast may receive some illustration from the evils resulting 

 from moisture to the plants of cold regions : Auriculas die unless the 

 moisture is drained from the pots in which they are kept ; and the 

 Saxifraga oppositifolia, and Rubus arcticus, plants which inhabit the 

 extreme north, rot from the dampness of our atmosphere. Its effects 

 upon arctic animals may, however, be guarded against by the precau- 

 tions already suggested as adapted to preserve tropical animals from 

 the influence of the raw cold of our climate. 



The greater part of the animals of northern regions, excepting 

 those which hibernate, migrate to more southern latitudes, where food 

 is more abundant and the cold less severe. Those which remain are 

 generally predaceous, and being reduced to the greatest necessity, 

 are voracious in the extreme. It is therefore a question whether in 

 our attempts to keep such animals they should not be placed on a 

 very low diet. This is also indicated by the fact that animals of cold 

 countries are less acted upon by cold than those of warmer climates ; 

 they approach apparently somewhat to the state of the cold-blooded 

 classes, and it is therefore probable that it would be improper to 

 exhaust their irritability by stimulating them at a period when nature 

 has provided that they should be in a state of subaction. Hiberna- 

 tion is the extreme of this state. It is a great resource established 

 by nature to obviate the evils of low temperature and privation. 

 In this condition the quadruped sinks to a state resembling that of a 

 reptile, its temperature scarcely exceeding that of the immediately 

 surrounding air, a state of existence which has been beautifully con- 



