EXAIS^INATION OF SERUMS MADE BY LICENSED MANUFAC- 
TURERS. 
The act of Congress approved July 1, 1902, entitled “An act to 
regulate the sale of viruses, serums, toxins, and analogous products in 
the District of Columbia, to regulate interstate commerce in said arti- 
cles, and for other purposes,’' and the regulations framed thereunder, 
approved February 21, 1903, imposed upon the Director of the Hj^gi- 
enic Laboratory the duty of examining vaccines and antitoxins for 
purity and potency. 
According!}^ purchases are made for the Hygienic Laboratory from 
time to time on the open market by officers of the Public Health and 
Marine-Hospital Service stationed in various parts of the country. 
The antitoxin is always bought from reliable druggists who keep the 
product under proper conditions of light, temperature, etc. Several 
grades of diphtheria antitoxin made b}^ each licensed manufacturer 
are bought and sent to the Hygienic Laboratory b}- mail for the pur- 
poses of these tests. 
The serums are tested not only for potency, but also to determine 
their freedom from contamination b^^ foreign bacteria, and finally to 
insure the absence of chemical poisons, especial!}" tetanus toxin. Note 
is made of the physical appearance of the serum, and tests are made 
to determine whether an excessive amount of preservative has been 
added. 
A careful memorandum is made of the facts given by the manu- 
facturer, as stated upon the label, as to the number of units contained 
in the package, and the date beyond which the contents can not be 
expected beyond a reasonable doubt to yield a specific result. Note is 
also made of the manufacturer’s compliance with the law requiring 
that the product be plainly marked with the name of the article, and 
the name, address, and license number of the manufacturer. 
Delinquencies that occasionally come to light in these examinations 
are at once reported to the Surgeon-General, U. S. Public Health and 
iMarine-Hospital Service, who takes the necessary steps requiring the 
immediate withdrawal of the particular lot of serum from the market 
and institutes measures to prevent a repetition of similar errors. 
In examining the unit strength of antitoxin sold by licensed manu- 
factures the first step is to measure carefully the quantity of fluid 
contained in the syringe, bottle, or special container, whatever it may 
be. For this purpose the serum is emptied into a cylinder that has 
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