Contagious Pleuro-Pneumonia of ilie Ox. Ala 



For convenience in division, not less than fortj-eight cattle, 

 dairy cows by preference, should be selected. Of these, twenty- 

 four should be, if possible, taken from a recently inoculated herd, 

 and twenty-four from a herd which was inoculated about a year 

 ago. The forty -eight cows should be divided into groups of four,, 

 and branded, so that no mistake as to identity could possibly 

 occur. To each group of inoculated animals an equal number 

 of healthy, uninoculated animals, also marked, and as nearly as 

 possible of the same character and condition, should be added. 

 Each group of eight cattle should then be sent into a shed or 

 field in Avhich there are animals affected with pleuro-pneumonia. 

 It is scarcelv necessary to allude to legal and financial difficulties 

 which stand in the way of the suggested experiment ; these must 

 be met, or the inquiry cannot be conducted. Nor is it required 

 to insist on the importance of competent supervision being pro- 

 vided in the case of each group of animals, both for the purpose 

 of guarding against the extension of disease and watching the 

 progress of the experiment. 



For some considerable time it would be necessary to record 

 the observations which would be made on the several groups of 

 cattle, without attempting to draw any conclusions from the 

 evidence. A year would not be an excessive time to wait for 

 the solution of an important question ; and it can hardly be 

 expected that the investigation would be satisfactorily concluded 

 before that period had elapsed. 



The second method of testing the value of inoculation as a 

 preventive of pleuro-pneumonia, by operating on the apparently 

 healthy animals in herds which have been attacked with the 

 disease, has to some extent been applied in many parts of the 

 country where pleuro-pneumonia has existed since inoculation 

 was introduced ; but the evidence which has been collected is so 

 indefinite that no conclusion based on it can be accepted. So- 

 lar as can be ascertained, no care is taken in the first instance to- 

 separate the animals which are infected from those in which there 

 are no indications of disease, and consequently, unless the action 

 of inoculation were curative as well as preventive, the results 

 would be seriously modified. It is claimed for the operation, by 

 some, that its action is beneficial to the infected animals. With, 

 better reason, however, others contend that the introduction of 

 the virus in such cases onlv adds fuel to the fire. 



Another circumstance which militates against the satisfactory 

 prosecution of an inquiry is the very natural desire of the owner 

 of the infected herd to get rid of suspected animals without delay. 

 When the cattle are in good condition, the most trifling symptom 

 of disease is sufficient to consign them to the butcher ; the slightest 

 loss of appetite, a little falling off in the quantity of milk, are 



