134 
HAROLD C. ERNST. 
of the Harvard Medical School, some of the microscopic 
work at the Society’s laboratory in Boston, whilst the feeding 
experiments have been done and the experimental animals 
have been kept at a farm in the country devoted to this espec- 
cial purpose, and situated among the healthiest possible sur¬ 
roundings. Nothing has been set down as the result of mi¬ 
croscopic observation that I have not myself verified, and 
every portion of the work has been carried out under the most 
exacting conditions, and with every possible precaution 
against contamination. 
Before the farm buildings were used at all they were thor¬ 
oughly cleaned from top to bottom. Every portion of old 
manure was carted away, as well as all the old earth. The 
whole of the woodwork was scrubbed and then washed 
with corrosive sublimate solution (i : 1000) and finally white¬ 
washed, and every care was taken to secure good drainage 
and free ventilation. The result and effectiveness of all this 
have been best demonstrated by the fact that every animal 
brought to the place made a most marked improvement in its 
general condition, while some of them even went so far as to 
appear to get well. 
In deciding whether the milk from any cow affected with 
tuberculosis is dangerous, when the udder shows no lesion, 
the first point is to see whether the milk contains the infec¬ 
tious principle or not. In this case, of course, that infectious 
principle is the bacillus of tuberculosis, and attention was 
turned to that for some time. The observations have been 
carried on over a long space of time, and were made as fol¬ 
lows : The milk was taken from the cow in the morning—or 
evening, as the case might be—the udders and teats having just 
been thoroughly cleaned. The receptacle was an Erlenmeyer 
flask, stoppered with cotton-wool and thoroughly sterilized 
by heat. The specimen was taken at once to the laboratory, 
there placed in conical glasses, with ground-glass covers—the 
whole of these having been carefully cleansed beforehand— 
and then allowed to stand in a clean refrigerator for twenty- 
four to forty-eight hours, and sometimes for seventy-two 
hours. 
