1002 VETEEINAEY HYGIENE 



pursued, the case would first be admitted for the attack of 

 colic and discharged relieved, re-admitted for constipation 

 and discharged relieved, and finally admitted for intestinal 

 calculus or enteritis and discharged ' died.' Therefore, 

 during one illness, this horse swelled the list of admissions 

 of two diseases which were only present in his particular 

 case as symptoms, and he would accordingly vitiate the 

 returns connected with the admissions and recoveries of 

 these diseases. If this method of collecting data be carried 

 out in a number of cases, it is easily seen how devoid of 

 value such statistical results must be. 



Every unit forming part of a series representing any 

 disease, must without doubt belong to this disease, and to 

 no other. If there is a doubt about it, omit the unit 

 entirely, and account for it under the heading of ' obscure.' 

 It is not the compiler of statistics who is answerable for 

 the correctness of the units, the responsibility rests with 

 those who furnish them. 



Group Building. — The second point to attend to is the 

 grouping or arranging of the figures, so as to analyze what 

 they really represent. This group building, as Parkes 

 said, seems simple ; but, in reality, ' to properly group 

 complex facts so as to analyze them, and to bring out all 

 the possible inferences, can only be done by the most 

 subtle and logical mind.' 



Let us suppose that we have collected the record of 

 1,200 cases of pneumonia, and wish to learn from them 

 the lessons they are certainly capable of teaching if we 

 only know how to extract them. We can ascertain the 

 various supposed causes, the mean duration of the affec- 

 tion, the effects of certain methods of treatment, the 

 mortality, etc. The portion of the inquiry of most interest 

 to the hygienist are the causes in operation and the mortality, 

 and one would probably find that some such plan as the 

 following would be the most suitable method of work — 

 viz., to study the influence of season, age, sanitation, work, 

 and the effects of strangles and influenza. These would 

 be termed the dividing characters. 



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