24 THE MODERN MILK PROBLEM 



deaths above five years of age) that about one-half of 

 1 per cent of all tuberculosis deaths are definitely due 

 to the bovine type. Another authority, Ravenel, holds 

 that there is a possibility of the bovine bacillus chang- 

 ing its type after becoming rooted in the human sub- 

 ject, which, if true, would mean that there is more 

 tuberculosis of bovine origin than we can now 

 prove. 



While the above estimated mortality is not very 

 great (amounting to about 500 deaths per year in the 

 Registration Area) as compared with the mortalities 

 from a number of other preventable diseases, it must 

 be remembered that there is a much larger number of 

 serious non-fatal cases and also that the amount of 

 tuberculosis from this source may be greater than is 

 now supposed. 



In a summary of the researches, Rosenau 12 states 

 that " about one-quarter to one-half of all cases of 

 tuberculosis in children under five years of age is as- 

 sociated with the bovine type," probably derived in 

 all cases from cow's milk. The great bulk of the human 

 tuberculosis bacteriologically identified as bovine is in 

 the form of generalized, abdominal, and glandular 

 tuberculosis of children. The percentages of mor- 

 tality given by Rosenau for the age-groups " under 5," 

 "5 to 14," and " 15 and over," when applied to the cor- 

 responding numbers of total tuberculosis deaths in the 

 U. S. Registration area for 1913 in those age-groupsi 

 result in a total of 1925 deaths, or 2.1 per cent of aft 

 tuberculosis deaths, as due to the bovine type. This 

 is considerably higher than the above estimate based 

 on Park's figure. Rosenau 13 himself says, "It is now 



