EXPERIMENT STATION BULLETINS. 557 



tion of property. There are cases where this would be legitimately allow- 

 able as we shall see later in a survey of reactions, but when it is applied 

 irrespective of other features it cannot be justified. Where there is a 

 possibility of five degrees of variation in normal maximal temperatures, 

 two degrees cannot be taken as the sole criterion for placing the stamp 

 of "tuberculous" upon an animal. 



It does seem incredible to learn from various sources that skilled men 

 have tested thousands of cattle with only two or three errors per thousand 

 and those errors on the side of obtaining no reaction in tuberculous 

 cattle, when normal temperatures of ninety-eight cattle belonging to the 

 M. A. C. herd, this spring, would have practically condemned four. If 

 the variation is taken as two degrees irrespective of days, nine would 

 have been condemned. (See above tables for March 28 and 29, 1898). 

 These temperatures were taken in exactly the same way as we would 

 take them in a regular test, omitting two or three hours in the early 

 morning. None of these variations occurred in the eleven cattle which 

 had already been condemned at a previous test. This certainly indicates 

 that we must proceed with much circumspection, otherwise, tuberculin 

 will be thrown into disrepute, notwithstanding the hyper-enthusiastic 

 spirit which is exercised in its behalf. Let us hold to its real value. 



SUDDEN CHANGES IN TEMPERATURE. 



We frequently find the maximal and minimal temperatures for the day 

 occurring within one hour of each other. This is of interest not only from 

 the suddenness of the change, but its bearing upon the interpretations 

 made. It is maintained by some operators that this suddenness of change 

 is due to the thermometer. Perhaps in some cases this is true, for where 

 a thermometer is encased, the case may become cold, so that, upon in- 

 sertion, the temperature would not be recorded accurately in three min- 

 utes time. I have met with this very trouble in the course of my work; 

 but when the taking of the temperature is repeated with the greatest 

 care and the temperature shows a sudden change, some other agency 

 must be at work. 



We wish to give some of these sudden changes as we find them scat- 

 tered through the tables. 



