328 
THE TUBERCULIN TEST IN MASSACHUSETTS. 
and, considering the two, Nos. 91 and 121, to be non-tnber- ^ 
culous, the percentage of accuracy is very great; slightly more ! 
than one per cent, of the animals were condemned unneces- | 
^ \ 
On the other hand, of the 20 animals selected from the re¬ 
mainder of the herds that were tested and not condemned, 6 
were found to be undoubtedly tuberculous, but none of them ex¬ 
tensively so. Of these 6, i (No. 15) presented but a single 
minute lesion, and that in an inactive stage, so that the proba¬ 
bilities are that her condition was one of recovery ; in at least 
3 others (Nos. 14, 18 and 20) the lesions were so small that it is ; 
an open question whether the infeetion might not have occurred ^ 
a/fej' the test was made, and before the examination,—a period j 
of, as I understand, five weeks. ^ 1 i, i 
Connting all of the apparent mistakes •as actual errors, how- | 
ever, it gives a percentage of variation of 5.5 ; the error in the | 
direction of unnecessary condemnation being much less than in | 
the line of allowing slightly infected animals to pass. ^ 
Respeetfnlly submitted, i 
Harold C. Ernst, A.M., M.D., 
Professor of Bacteriology in Harvard University. 
report of THEOBALD SMITH, M.D., 
Professor of Comparative Pathology in Harvard University. 
Jamaica Plains, Mass., May 10, 1897. 
To the Special Joint Committee authorized to hivestigate certain cattle belonging to 
farmers of Dracut and Lowell. 
Gentlemen :—It has been possible for me to attend the 
post-mortem examination of 112 of the cattle condemned by the 
tuberculin test. Of this number I regard 4 as free from tuber¬ 
culosis and 108 as infected. 
The infected I have divided, in accordance with the notes 
taken at the autopsies, into five categories, according to the 
severity and extent of the disease. In these five categories the 
animals may be tentatively placed as follows : 
22 in first category (very slight disease). 
36 in seeond category (slight disease). 
28 in third category (moderate disease). 
16 in fourth category (fairly severe disease). 
8 in fifth category (extensive disease). 
Of the 20 animals killed, which had failed to react after the 
