120 ARON. 



of long training, -who was also able to read the galvanometer. How- 

 ever, I generally preferred to do this more responsible part of the work 

 myself. 



After adjusting the apparatus, taking the zero point of the galvano- 

 meter and being sure that the- place of junction was being kept for at 

 least five minutes within 0°.l, the thermometric junction was warmed in 

 the palm of the hand and then placed on the different parts of the skin, 

 which were to be measured. The metal leaf must just slightly touch the 

 skin, and must be kept at one place until the galvanometer just reaches 

 its maximum deviation; with my apparatus twenty seconds was almost 

 more than sufficient for this pur]3ose. Especially in experiments con- 

 ducted in the sun, the place to be measured must not be touched too 

 long, because the thermometer itself casts some shade. According to 

 Kunkel's suggestion I have measured falling as well as rising tem- 

 peratures, but I observed no difference between them. 



It is more tedious to take the temperature in the hair or under clothes. 

 Here a thermocouple of the second type must be left for three or four 

 minutes until the maximum of deflection is reached. Care must be taken 

 to have the metal well covered by hair in taking the temperature of the 

 air in the hair. 



The skin temperatures at different parts of the body, . especially that 

 of the head and arms, were first measured on a number of people, both 

 white and brown, inside of a room and also in a shady place outdoors. 

 The values obtained vary within the extreme limits of 31° to 34°, the 

 greater part of the skin showing temperatures between 32°. 5 and 33°. 5. 

 The values given by Kunkel for a room temperature of 20° are nearly 

 1° higher on an average than those of Eubner for temperatures of 25°. 6 

 and 26°. 5, and then my figures are for room temperatures of 26° to 

 30°. My figures agree very well, on an average, with those of Reichen- 

 bach and Heymann. Different places on the skin do not have exactly 

 the same temperature ; that over thicker muscular parts or over abundant 

 fat being always higher, often as much as 1°, than that found in places 

 where the bones lie closely under the skin. This is very pronounced 

 over the malar bones, and on the hand. The highest temperatures gen- 

 erally occur on the forehead and neck ; the palm of the hand is always 

 warmer than the back, and similar variations occur in other parts of the 

 body. Care should be taken always to measure the temperature on a dry 

 skin; wet skin gives different values. Table YII shows normal values 

 for the skin temperatures as obtained from a number of experiments on 

 different people. The values given by Eubner and Kunkel are placed 

 beside them for comparison. 



