792 ANIMAL HEAT. 



rhynchus anatinus) from 24 -4: to 25'2. In the case of birds the 

 temperature is generally two or three degrees higher than that of 

 mammals. 



In the observation of the temperature of animals, it is necessary, 

 if comparable results are to be obtained, to insert the thermometer 

 to a similar extent each time, and to prevent struggling of the animal 

 before and during the time of observation. Tinkler 1 found that the 

 rectal temperature of guinea-pigs was 36'l, 387, and 38 0> 9, at a depth 

 of 2'5, 6, and 9 cms. respectively. Aronsohn and Sachs 2 found 

 that the rectal temperature of normal rabbits rose to over 40 after 

 a short chase, Hobday 3 observed a rise to 41'l in the case of sheep 

 and pigs, and Mott 4 has noticed a *ise of one or two degrees in the 

 temperature of monkeys, owing to a similar cause. Moreover, the times 

 of observation should as far as possible be similar, for animals show 

 a daily variation in temperature. Eabbits extended on their backs and 

 tied down lose so much heat that their temperature rapidly falls 

 (Legallois, Eichet: 5 ) 



The temperature of cold-blooded animals. It has already been 

 shown that there is no hard and fast line between the so-called warm-blooded 

 animals those with a constant temperature, and the cold-blooded animals 

 those with a varying temperature. Further proofs of this will now be given, 

 and others will be brought forward when the subject of hibernation is 

 considered. 



John Hunter 6 made some interesting observations upon the temperature 

 of bees. He found in the month of July, when the temperature of the air was 

 12*2, and a north wind was blowing, that the temperature at the top of a hive 

 full of bees was 27'8. In December the temperature of the hive was 22 '8, 

 when that of the external air was only 1'7. A single bee has so little power 

 of keeping itself warm, that it quickly becomes numb and almost motionless 

 when exposed to the moderate cold of a summer night. The aggregation, 

 however, of vast numbers in a hive ensures the production of enough heat to 

 keep the bees active even in winter, and for this production of heat a constant 

 supply of food is necessary. The warmth of the hive is needed also for 

 the eggs, pupae, and larvae, for Hunter found that they would not live in a 

 temperature of 17. The wax is by means of the warmth kept so soft that the 

 bees can model it with ease. 



Numerous observations upon the temperature of bees were made by 

 Newport, 7 who found that, when the insects were in a state of activity, 

 their temperature was above that of their surroundings ; the larva and pupa 

 had a lower temperature than the imago, and less power of generating as well 

 as of maintaining their temperature. In winter the temperature of a hive, 

 when the bees were in a state of repose, fell considerably, and varied slowly 

 with that of the atmosphere ; the bees did not become torpid, but passed into 

 a deep sleep, broken at intervals by periods of activity. A very low atmo- 

 spheric temperature aroused the bees, and thus prevented any great fall in the 

 temperature of the hive. Thus on January 2, 1836, at 7.15 A.M., when the 

 temperature of the air was -7*5, that of the hive was -l'l, and the bees were 

 quiet, but after the bees were disturbed by tapping the hive, the temperature 



1 Arcli.f. d. ges. Physiol., Bonn, 1882, Bd. xxix. S. 117. 

 -Ibid., 1885, Bd. xxxvii. S. 232. 



3 Journ. Comp. Path, and Therap., Edin. and London, 1896, vol. ix. p. 286. 



4 Note communicated to the writer. 



5 Rev. sclent., Paris, 1884, tome viii. p. 300. 



6 "Works," Palmer's edition, London, 1837, vol. iv. p. 427. 



7 Phil. Trans., London, 1837, pt. 2, p. 253. 



