248 BACTERIOLOGY 



OBSERVATION OF ANIMALS AFTER INOCULATION. After 

 either of these methods of inoculation, particularly when 

 unknown species of bacteria are being tested, the animal is to 

 be kept under constant observation and all deviations from 

 the normal are to be carefully noted as, for instance, eleva- 

 tion of temperature; loss of weight; peculiar position in 

 the cage; loss of appetite; roughening of the hair; excessive 

 secretions, from either the air-passages, conjunctiva, 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 sometimes occurs, however, 

 that inoculation results in the production of chronic con- 

 ditions, and the animal must be kept under observation 

 often for weeks. In these cases it is important to note the 

 progress of the disease by its effect upon the physical condi- 

 tion 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 mid- 

 way between the hours of feeding; at the same time its 

 temperature, as indicated by a thermometer placed in the 

 rectum, is to be recorded. 1 By comparison of these daily 

 observations the observer is aided in determining the course 

 the infection is taking. 



Too much stress must not, however, be laid upon moderate 

 and sudden daily fluctuations in either temperature or 

 weight, as it is a common observation that presumably 



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. 



