382 METHODS OP ESTIMATING THE TEMPERATURE. 



An instance of this great constancy of the temperature in the human body 

 was furnished by Fordyce, who died in 1792. After a man had been for ten 

 minutes in a room filled with hot, dry air, the temperature of the interior of his 

 closed hand, the cavity of his mouth beneath the tongue, as well as the urine, 

 was raised only a few tenths of a degree. When Becquerel and Brechet were inves- 

 tigating by means of the thermo-electric needle the temperature in the middle of 

 the biceps muscle in a man whose arm had been immersed for a whole hour in 

 ice-water, they found the temperature of muscular tissue reduced only 0.2 C. 

 The same muscle exhibited either no increase in temperature or a reduction of 

 only 0.3 C. after the man had immersed the arm in water at a temperature of 

 42 C. for a quarter of an hour. 



If marked alteration in temperature be brought about by powerful 

 agents, namely, by vigorous abstraction of heat or by considerable 

 addition of heat, great danger to the continuance of life results. 



Poikilothermic animals react differently, the bodily temperature 

 following in general the surrounding temperature, though with varia- 

 tions. On the basis of numerous observations Soetbeer therefore states 

 that the poikilothermic vertebrates have no special temperature in the 

 ordinary sense of the term, but their bodily temperature, like that of 

 inanimate objects, is dependent upon that of the physical conditions of 

 their surroundings. 



The following may suffice as illustrations of the bodily temperature in the 

 animal kingdom: Birds: sea-gull, 37.8 C.; swallow and titmouse, 44.03; mam- 

 mals: dolphin, 35.5, mouse, 41.1, echidna from 26.5 to 36; arthropods: from 

 0.1 to 5.8 above the surrounding temperature; in bees aggregated in the hive 

 from 30 to 32, and in bees in swarms as high as 40. The following animals 

 raise their temperature above the surrounding temperature: cephalopods 0.57, 

 molluscs 0.46, echinoderms 0.40, medusae 0.27, polyps 0.21 C. 



METHODS OF ESTIMATING THE TEMPERATURE: 

 THERMOMETRY. 



Thermometry. By means of thermometric apparatus information is obtained 

 as to the temperature of the body subjected to examination. For this purpose 

 there are employed: 



The thermometer (Galileo, 1603). Sanctorius was the first in 1626 to make 

 thermometric measurements in human beings. It is advantageous to employ 

 instruments ^ graduated in 100 parts according to Celsius, each degree being 

 subdivided into ten parts. The apparatus should be compared with a nor- 

 mal thermometer before being used. The column of mercury should be slender 

 and the spindle neither too small nor too large, and preferably cylindrical in 

 shape. A large bulb increases the sensitiveness and also the period of observation, 

 because the large amount of mercury is influenced through and through by heat 

 with greater difficulty. If the spindle be smaller the observation can be made 

 more rapidly, but it is less trustworthy. The scale should be of porcelain. 



All thermometers acquire an error after use for a considerable time, regis- 

 tering too high. Therefore, they should be compared from time to time with a 

 normal instrument. At every observation the bulb should be completely sur- 

 rounded and kept at rest for at least fifteen minutes and during the last five 

 minutes no movement in the column of mercury should be noticeable. Minimal 

 and particularly maximal thermometers, for the measurement of febrile tempera- 

 ture, are of the greatest convenience to the physician. 



For delicate comparative measurements Walferdin's metastatic thermometer 

 (Fig. 134) is especially useful. The tube is exceedingly narrow in proportion to 

 the bulb. In order that on this account the instrument should not be drawn out 

 to an extraordinary length, an arrangement is provided by which the necessary 

 amount of mercury can be increased or diminished at will. So much mercury is 

 taken that at the expected temperature the column reaches about to the middle 

 of the tube. This end is attained by having at the upper extremity of the tube 

 an expansion in which the superfluous mercury is received. If, for instance, a 

 temperature is to be taken that is likely to be between 37 and 40 C., the bulb 



