212 BACTERIOLOGY. 



the animal is to be kept under constant observation and 

 all that is unusual in its conduct noted as, for instance, 

 elevation of temperature ; loss of weight ; peculiar posi- 

 tion in its cage ; loss of appetite ; roughening of the hair ; 

 excessive secretions, either from the air-passages, con- 

 junctiva, or kidneys ; looseness of or hemorrhage from 

 the bowels ; tumefaction or reaction at site of inoculation, 

 etc. If death ensue in from two to four days it may 

 reasonably be expected that at autopsy evidence of either 

 acute septic or toxic processes will be found. It some- 

 times occurs, however, that inoculation results in the 

 production of chronic conditions, and the animal must 

 be kept under observation often for weeks. In these 

 cases it is important to note the progress of the 

 changes by their effect upon the physical conditions 

 of the animal, viz., upon the nutritive processes as 

 evidenced by fluctuation in weight, and upon the body 

 temperature. For this purpose the animal is to be 

 weighed daily, always at about the same hour and 

 always about midway between the hours of feeding ; at 

 the same time its temperature as indicated by a ther- 

 mometer placed in the rectum is to be recorded. 1 By 

 the comparison of these daily observations with one an- 

 other, one is aided in observing the course the infection 

 is taking. 



Too much stress must not, however, be laid upon 

 moderate and sudden daily fluctuations in either tem- 

 perature or weight, as it is a common observation that 

 presumably normal animals when confined in cages and 



1 The thermometer must be inserted into the rectum beyond the grasp of 

 the sphincter, otherwise pressure upon its bulb by contraction of this muscle 

 may force up the mercurial column to a point higher than that resulting 

 from the actual body temperature. 



