DISEASES OF UNKNOWN ETIOLOGY ()o7 
vaccination.^ The extreme rarity of these cases and the possibility 
of infection from uncleanly conditions after the vaccination was 
made make it doubtful that vaccine may be a vehicle for the trans- 
mission of tetanus.'- 
The addition of the glycerin to the pulp obtained from vaccinated 
calves pla>s an important part in reducing the number of bacteria 
which are invariably present in "green vaccine"— it does not seriousl>' 
impair the activity of the virus itself. After one to two months' 
storage, which is generally practiced to reduce the number of bac- 
teria, the vaccine is relatively free from microorganisms, although it 
is practically never sterile. 
The ripened vaccine is subjected to a bacteriological examination 
to determine the number of bacteria per cubic centimeter, the absence 
of tetanus bacilli and streptococci, and a guinea-pig inoculation is 
made with about a cubic centimeter of it to guard against an acci- 
dental excess of carbolic acid, before it is tested clinically for its 
potency. The potency test is made upon several children (previously 
unvaccinated) in the usual manner. Generally at least a dozen cases 
are vaccinated and a high percentage of "takes" must be obtained 
before the product is finally marketed. 
Xoguchi^ has cultivated an absolutely sterile vaccine virus of high 
potency in the testes of rabbits and bulls. The entire freedom of 
the preparation from alien microorganisms not only eliminates the 
necessity of a ripening process to reduce bacterial contamination; 
it also makes it possible to reduce the cost of production materially. 
The vaccinal eruption induced in the cornea, skin and testes of rabbits 
and the skin eruptions in calves were identical with those induced 
by the virus perpetuated in the ordinary manner. The eruptions 
induced in man also were perfectly typical. Finally, the sterile tes- 
ticular vaccine induced immunity reactions in experimental animals 
identical with those obtained with the ordinary "skin" vaccine. 
Phenomena of Vaccination. — 1 . Techniqve.— The site of vaccination, 
preferably the outer aspect of the arm about the deltoid muscle, is 
cleansed thoroughly with soap and water, and finally with alcohol 
if possible. When the surface is dry a light scratch about 1 inch 
long is made with a sterile needle,* deep enough so that the bottom 
of the incision is slightly reddened, but not deep enough to draw blood. 
The virus is then spread over the area and brought into intimate 
contact with the epidermal layer by gentle rubbing with the side of 
the needle. The safest method of vaccination is by puncture either 
with a charged needle, or through a shallow abrasion made with a 
1 Wilson: Jour. Am. Med. Assn., 1902, 38, 1147, 1222. McFarland: Jour. Med. 
Res., 1902, 7, 474. 
2 See Francis (Bull. No. 95, U. S. P. H. and Marine Hospital Service, 1914) for results 
of implanting tetanus spores directly into vaccine; also Anderson (Trans. Assn. Am. 
Phys., 1915, 30, 386). 
3 Jour. Exp. Med., 1915, 21, 539; 1918, 27, 425. 
* An ordinary sewing needle is excellent for the purpose. 
42 
