BY DR. BURDON-S ANDERSON. 343 



die ; the pulse and respiration being first accelerated and then 

 diminishing. Associated with this last change is a very rapid 

 loss of temperature, while the urine becomes albuminous. 

 Formerly it was supposed that these changes were dependent 

 on the suspension of respiration. It is easy, however, to prove 

 experimentally that it is not so by placing the animal in a 

 chamber at a temperature of about 30 C., when it is seen 

 that as the temperature of the body rises the other symptoms 

 disappear. Even if the animal has been allowed to cool as 

 low as 21.l C. it can be restored by warmth. By placing a 

 varnished rabbit in the calorimeter, it can be shown that al- 

 though its temperature is actually 10 or more below that of 

 the surrounding air, it gives off a great deal more heat than a 

 normal rabbit. Thus I find that a rabbit, which in the normal 

 state gives off only 3000 heat units in ten minutes, gives off 

 about 20,000 after varnishing, notwithstanding that in the 

 former case its temperature was constant at 39.5 C., while in 

 the other it sank from 36 to 25. 



SECTION II. THERMOMETRY. 



The temperature of the animal body is measured either by 

 the mercurial thermometer or thermo-electrically : 



118. Measurement of Temperature by the Mercu- 

 rial Thermometer. The mercurial thermometer used for 

 physiological (as well as for pathological) purposes should 

 have the following characters. The proportion between the 

 quantity of mercury contained in the bulb and the lumen of 

 the tube must be such that the difference of length of the 

 column produced by any given increase of temperature shall 

 be as great as possible. One degree of the centigrade scale 

 should be sufficiently distant from another to render it possi- 

 ble to read easily to a tenth. On this account the range of 

 graduation is necessarily limited. It is sufficient if it extends 

 from 30 to 45 C. The bulb must expose a large surface in 

 proportion to the volume of mercury it contains ; for which 

 reason it is made cylindrical. The most celebrated thermo- 

 meters are those of Dr. Geissler, of Bonn. They are 32 centi- 

 metres ( = 12 inches) long, and relatively exceedingly narrow 

 only a line arid a half in diameter. The cistern is no wider 

 than the stem, and is eight-tenths of an inch long. Mr. Hawks- 

 ley, of Blenheim Street, has recently constructed for me in- 

 struments which are very similar and comparable in quality 

 to those of Geissler. The bulbs and stems are of equal diame- 

 ter throughout, not exceeding three millimetres. They are 

 extremely sensitive, and the graduation is so fine that to the 

 practised observer it is easy to read accurately to the 50th of 

 a degree of Celsius. 



