714 
contain in order to permit its lawful sale as whole milk is 3.5 per cent. 
This standard is a reasonable one and should insure the sale of a 
high-grade article. At times, however, even the most careful dealer 
may allow his milk to fall below it. The practice of the department 
requires that wherever a sample of milk is found to contain added 
water or a preservative, or to be colored, or to contain less than 3.25 
per cent butter fat. prosecution is to be instituted as a matter of 
course. If the butter fat is 3.25 per cent or more, but less than 3.5 
per cent, then prosecution is or is not instituted according as the 
entire recent record of the vendor is good or bad. If his milk has 
been repeatedly below 3.5 per cent, then even though the present 
sample shows more than 3.25 per cent, prosecution is instituted. In 
cases within this class, where the element of judgment enters, the 
inspector submits with his report and recommendations a statement 
showing the recent record of each vendor. A similar practice is in 
force with respect to cream, the legal standard for butter fat being 
20 per cent, and prosecution being instituted as a matter of course 
if the amoimt contained in a given sample falls below 18 per cent, 
and being instituted or not. according to the entire recent record of 
the vendor, where the amount of butter fat is 18 per cent or more and 
yet less than 20 per cent. 
In the chemical laboratory are analyzed samples of water from 
wells on dairy farms. These samples are collected by inspectors of 
rms, and if fi . near- r farms are i ught to the chemist 
the inspector. If from outlying farms, as, for instance, those in the 
Frederick district, samples are forwarded by express. 
COOTAGIOTJS-DISEASE SERVICE. 
Attention has already been called to the difficulty which an in- 
spector of dairy farms incurs in any effort that he may make to 
detect on the farm cases of communicable diseases, such as typhoid, 
scarlet fever, or diphtheria. For the information of those of the 
readers of this report who are not familiar with technical matters re- 
lating to milk inspection, it is necessary to add that by no known 
method of chemical or bacteriological analysis can the possibility, or 
even the probability, of the presence in milk of the typhoid bacillus 
or the diphtheria bacillus be excluded with any reasonable degree 
of certainty : that the colon bacillus is a not infrequent inhabitant of 
milk, its presence indicating merely contamination with the excre- 
ment of the cow and not even suggesting sewage pollution : and that 
the organism that causes scarlet fever is as yet entirely unknown. 
Under such circumstances, the following method has been adopted to 
facilitate the detection of contagious diseases on the daily farm : 
