Investigations into the conditions governing tlie temperature of thie bodз^ 7 



structed for the mouth readings. The thermometers have been made 

 small, the receiver has been given the form of a two-pronged fork, 

 the whole thermometer has been shaped like a bayonet, and finally 

 these different forms have been combined. One may, of course, 

 grow accustomed to the use of a thermometer, even if the shape 

 is unpractical, and even with the best thermometers the readings in 

 the mouth require a certain amount of training, before reliable 

 results can be obtained; nevertheless, I do not hesitate to maintain 

 that the mouth thermometer ought to be shaped like a bayonet, as 

 it is only with such a thermometer that the tongue remains in its 

 natural position and that the lips can meet spontaneously and keep 

 the mouth closed without effort; consequently, that the muscles of 

 the mouth and face can remain quiet during the reading. 



Further, the temperature ought always to be measured in the 

 same place, which is most easily attained by carrying the receiver 

 of the thermometer as far back as possible into the sulcus alveolo- 

 lingualis; it will therefore be practical to have the thermometer of 

 such dimensions that the distance from the end to the first bend 

 corresponds with the distance from the posterior limit of the sulcus 

 to the row of teeth (about 45 centimeters). Since the temperature 

 of the mouth, as will be shown later, is to a high degree dependent 

 upon the external temperature, it is reasonable to assume that the 

 temperature is not always the same in the front, comparatively 

 thin-walled part of the mouth and in the hinder, more sheltered 

 part. I cannot show this by figures, because a small thermometer 

 taken for this purpose was lost all too early; but what I have found 

 tends in the direction mentioned. Finally, the receiver of the ther- 

 mometer ought to be single not forked; for the temperature need 

 not be the same in the two sides of the mouth, and a mean tempe- 

 rature is of no particular interest, as the mouth readings are not 

 adapted to clinical use. 



As regards the time occupied by a reading, it seems as if the 

 thermometer is somewhat longer in adjusting itself in the mouth 

 than in the rectum, which is partly due to the anatomical and 

 physical conditions; for my measurements also, no doubt, to the 

 thermometer itself. As a rule 5 minutes will prove sufficient; but 

 to make sure of the result, especially if the thermometer has been 

 much cooled down before use, one ought to let it remain in for 

 about 10 minutes. 



On measuring one's own temperature, as I have done, we may 

 control the amount of rise by means of a mirror. On taking a 

 series of mouth readings, beginning with a very cold thermometer, 

 it has proved, that we run the risk of obtaining too low a result in 



