THERMOMETRY. 



319 



Poikilothermal animals behave very differently; the temperature of their 

 bodies generally follows, although with considerable variations, the temperature of 

 the surroundings. When the temperature of the surroundings is increased, the 

 amount of heat produced is increased, and when the surrounding temperature falls, 

 the amount of heat evolved within the body also falls. 



The following table shows very clearly the characters of poikilothermal animals, e.g., frogs, 

 which were placed in air and water of varying temperatures. They were immersed up to the 

 mouth. The temperature was measured by means of a thermometer introduced through the 

 mouth into the stomach. 



[Temperature of Different Animals. 



Birds. 



Thalassidroma, 



Procellaria, 



Goose, 



Sparrow, . 



Pigeon, 

 Turkey, . 

 Guinea-fowl, 



Duck, 



Crow, 



41-80- 



Temp. 

 40-30 

 40-80 

 41-70 

 39-08 

 42-10 

 42-50 

 42-70 

 43-90 

 43-90 

 42-50 

 41-17 



Swallow. 

 Gull, 



Temp. 

 44-03 

 37*8 



Mammals. 



Tiger, . 

 Horse, . 

 Rat, 



Hare, . 

 Cat, . 

 Guinea-pig, 



Dog, . 



. 37*20 



36-80-37-50 



. 38-80 



. 37-80 



-38-90 



38-80 



37*40 



39-00 



39-60 



30- 



Panther, . 

 Mouse, 

 Dolphin, . 



Sheep, 



Ape, 



Guinea-pig, 

 Rabbit, . 

 Ox, . 



Ass, 



(Gavairet < 



Temp. 



. 38 



. 41 



. 35 



( 37-30-40 



^39-50-40 



/ 40-00-40 



. 35 



35-76-38 



. 37-50-38 



. 37 



. 36 



Rosenthal). 



90 

 1 



5 



00 



00 



50 



50 



00 



00 



50 



95 



Reptiles Snakes, 10-12, but higher when incubating. Amphibians and fishes 0'5-3 

 above the temperature of the surroundings. Arthropocla 0*l-5'8 above the surroundings. 

 Bees in a hive, 30-32, and when swarming, 40. The following animals have a temperature 

 higher than the surrounding temperature : Cephalopods, 0'57; molluscs, 0'46; echinoderms, 

 0-40; medusae, 0-27; polyps, 0*21 C. 



208. ESTIMATION OF TEMPERATURE. By using thermometry apparatus, we are 

 enabled to obtain information regarding the degree of heat of the body to be investigated. For 

 this purpose the following methods are employed : 



A. The Thermometer. Celsius (1701-1744) divided his thermometer into 100 parts, and 

 each part was again divided into 10 parts, so that -^ C. could be easily read off. All thermo- 

 meters which have been used for a long time give too high readings, hence they should be com- 

 pared, from time to time, with a normal thermometer. When. taking the temperature, the 

 bulb ought to be surrounded for fifteen minutes, and during the last five minutes the mercury 

 column ought not to vary. A very sensitive thermometer will indicate the temperature after 

 seven seconds if the urine stream be directed upon its bulb. Minimal and maximal thermo- 

 meters are often of use to the physician. 



[Clinically, one of the thermometers shown in fig. 228 may be used. They are self-registering 

 maximum thermometers, i.e., a portion of the mercury is separated from the mercurial column, 

 to form the index, the top of which indicates the temperature. Before being used, the index 

 must be well below the normal temperature. Various forms of surface thermometers have been 

 used. ] 



Walferdin's metastatic thermometer (fig. 229) is specially useful for comparative observation. 

 The tube is very narrow in comparison with the bulb, and in order that the stem be not too 

 long, it is constructed so that the amount of mercury can be varied. A quantity of mercury is 

 taken, so that with the temperature expected the thread of mercury will stand about the middle 

 of the stem. A small bulb at the upper part of the stem receives the excess of Hg. Suppose a 

 temperature between 37- 40 C. is to be measured, the bulb is first heated a little over 40 C, 



