474 Observations on Contagious Pleuro-Pneumonia of the Ox. 



signs which are surely accepted by the owner as significant of 

 the existence of disease in the incipient form, and he does not 

 feel disposed to wait for any further development of the malady, 

 to his own certain loss. This circumspection on his part leads 

 to the slaughter of many animals which were at the time per- 

 fectly healthy, and possibly might have remained in that con- 

 dition. At least the proceeding interrupts the inquiry and 

 renders it impossible to draw any inference from such incomplete 

 evidence. To carry into effect the second method of investiga- 

 tion properly it would be imperative to prevent any interference 

 with the herds under observation. 



Immediately on the appearance of pleuro-pneumonia, or as 

 soon as information of the existence of disease was obtained, the 

 internal temperature of every animal should be ascertained by 

 means of the thermometer before inoculation, and from time to 

 time during the experiment. There can be no objection against 

 the inoculation of every one of the herd : but it is essential that 

 the obserrer should know whether he is operating on infected or 

 perfectly healthy animals. Presuming that it is intended to dis- 

 cover what amount of protection will be afforded by inoculation 

 of a herd in which an outbreak of pleuro-pneumonia has occurred, 

 it is obvious that the proper course will be to allow the diseased 

 animals to remain in the shed or pasture with the others. The 

 sick beasts would be subjected to treatment, and in the event of the 

 disease advancing so far as to render recovery hopeless, they would 

 be destroyed, as they would be under ordinary circumstances ; 

 but no special care should be taken to prevent the exposure 

 of the inoculated animals to the influence of the contagium. 



Very commonly inoculation forms merely one of a series of 

 preventive measures, among which slaughter of diseased and 

 isolation of infected animals, with the liberal use of disinfectants, 

 play important parts. To attribute the cessation of the disease, 

 under such circumstances, to the influence of inoculation, is 

 indicative of a desire to evade the whole question. If slaughter, 

 isolation, and disinfection, are sufficiently active preventive mea- 

 sures to arrest the progress of the disease, inoculation is unne- 

 cessary. But if by inoculation the system is rendered unsus- 

 ceptible to the influence of the contagium, other means are not 

 required : indeed, in an inquiry of the kind suggested they are 

 objectionable, as being calculated to mislead. 



It is undoubtedly desirable that both the methods of investi- 

 gation which have been described should be conducted simulta- 

 neously on an extensive scale ; but there is no reason to doubt 

 that the first scheme, if properly carried into effect, is calculated 

 to furnish more correct evidence of the value of inoculation than 

 any which has yet been obtained. 



