EXPERIMENT STATION BULLETINS. 525 



allowed anything to stand in the way. A detailed description of how we 

 proceeded may be in order to justify us in saying that so far as practicable 

 we tried to obtain the truth. 



Thermometers. — Much is said about the use of thermometers. It is true 

 that thermometers may lead astray; not only the thermometer itself but 

 the reader also. For our use we obtained the English Hick's clinical 

 thermometers with patent lens front to facilitate reading. The thermom- 

 eters are self-registering and have an indestructible index which will 

 not become obliterated by frequent use. The certificate of examination 

 and correction accompanies each thermometer. These thermometers are 

 very expensive, costing in the neighborhood of $2.50 each at retail prices, 

 consequently cannot be recommended for ordinary testing. I believe these 

 thermometers are correct, for in the various tests I have made of them 

 I have not found them otherwise than represented. If error has occurred 

 in my work, I cannot attribute it in any large part to the thermometer. 



In using the thermometers I bound them at the lower and upper ends to 

 a strong glass rod about one quarter inch in diameter. This was done 

 for the purpose of protecting the fragile thermometers and of keeping 

 them clean with a disinfecting solution. The metallic cases commonly 

 used for protection cannot be kept clean, and they do not give as free 

 exposure to the bulb of the thermometer as when attached to a glass rod. 

 For ordinary work, however, I do not think that I would substitute the 

 glass rod for the metallic case, for the metallic case gives greater protec- 

 tion to the thermometer and there is less likelihood of breaking. To the 

 upper end of the glass rod and thermometer a string is tied which has a 

 hook on the end. This enables the operator to hook the thermometer, 

 when inserted, to a string which is stretched around the cow in front of 

 her hips. 



In managing the thermometer, the operator first shakes it down below 

 the 97° mark; this is checked by the recorder of temperatures who ac- 

 companies him. The thermometer is then inserted into the rectum to its 

 very top end and the hook attached to the string around the body to pre- 

 vent falling to the floor should the animal defecate suddenly. Three 

 minutes are allowed for the necessary time to obtain the correct tem- 

 perature of the animal. The time is put down on paper by the recorder 

 when the operator calls out its insertion; and the thermometer is taken 

 out only when the three minutes are up by the watch. The operator with- 

 draws it when so ordered by the recorder, carefully wipes it off so that the 

 index may be easily seen by the reader, hands it first to the recorder who 

 reads it in silence. The recorder hands it then to the operator who reads 

 it aloud. If the readings check each other, it is then recorded; if not they 

 study it carefully till they can agree. If there is any plausible question 

 about the temperature, they take the temperature again. After the read- 

 ing, the mercury is shaken down by the operator below 97° and checked 

 by the recorder. The thermometer is carefully wiped off and dipped into a 

 disinfecting solution. From this the end is dipped into carbol-vaseline 

 and inserted into the next cow. 



The checking system I deem very essential for accurate results, for 

 even old readers are likely to make serious errors after the monotony is 

 on, and new readers make many and very grave blunders, but by constant 

 correction they soon become able readers. After three hours of steady 

 employment, they make no more failures than do old readers. They be- 

 come very proficient. 



