38 



trasted by M. Edwards with the summer condition of the same animal. 

 Mr. Cox adverted particularly to the more remarkable phenomena of 

 hibernation, which, he stated, were now undergoing the investigation 

 of Dr. Marshall Hall, who was about to lay the result of his experiments 

 on this subject before the Royal Society. 



Mr. Cox then proceeded to recapitulate the practical remarks which 

 had resulted from his previous observations, and which in the present 

 abstract have been embodied with them. He afterwards entered 

 into the consideration of temperature, and dwelt particularly on 

 the importance of maintaining it at a sufficiently high degree in 

 all collections of tropical animals. On the question as to the degree 

 which might safely be regarded as sufficient, he remarked that if ana- 

 logies drawn from the vegetable kingdom could be depended on, 

 reference might be made to a temperature of from 50° to 90°, being 

 that of the noble Palm-house of Messrs. Loddiges, in which those 

 natives of tropical climates nourish admirably. But it is evident 

 from experience that 50° will be sufficient to keep tropical animals 

 alive in this climate, and a temperature of from 50° to 55° will pre- 

 serve them in health and activity. To induce them to breed with us, 

 that temperature will not be high enough, for an emasculating effect, 

 as has been observed by Mr. Yarrell in the Peccary and other ani- 

 mals, is produced by a cold climate : the few instances in which some 

 of the Fells tribe have been fruitful in this country, being only to be 

 regarded as exceptions. To develope the organs of reproduction in 

 plants, a higher degree of temperature than that suited for their mere 

 preservation is required; this rule may be equally applicable to ani- 

 mals, and the temperature of repositories for those of tropical climates 

 should therefore probably be allowed to alternate between 55° and 70°. 

 Mr. Cox repeated his opinion that sufficient humidity should at the 

 same time be provided. 



Mr. Cox concluded by stating that he had long been of opinion 

 that the best test for the proper state of the atmosphere in a mena- 

 gerie is vegetation. If the plants of a tropical or warm latitude thrive, 

 he conceives that the temperature and state of atmosphere (for it is 

 not temperature alone which we have to regard, but the other qualities 

 of the atmosphere also, moisture, elasticity, &c.) cannot be far removed 

 from those required for animals of the same latitudes. He assumes 

 that a perfect Vivarium should include within its area a conservatory 

 containing plants, natives of countries of a character similar to that 

 of the animals inclosed. No apprehension need, he thinks, be en- 

 tertained of plants contaminating the air to any injurious degree, 

 if proper ventilation were established, and abundance of fresh unre- 

 spired air were supplied : the contrary would in fact be frequently 

 the case during the day-time, the experiments of Priestley having 

 shown that the purity of air vitiated by the breathing of animals is 

 restored by the growth of living and healthy vegetables freely ex- 

 posed to the solar light. 



