7 
tetanus, malignant edema, anthrax, and the like. In 80 and 90 per 
cent glycerin, we have kept as common and as easil}" destroj^ed an 
organism as the golden pus coccus alive forty-one da}^s; the colon 
bacillus lived seventy days in 60 per cent glycerin; anthrax spores 
remaine4 alive and virulent two hundred and seventy-eight da}"s in 
gh'cerin. This work will soon be made the subject of another report. 
Glycerin, therefore, can not take the place of care and cleanliness 
in the preparation of vaccine virus. 
The effect of mixing glycerin with the virus is to gradually destroy 
both the bacteria and the vaccine, but fortunatel}’^ the ordinary pus 
cocci and nonsporulating bacteria generally succumb before the viabil- 
ity of the vaccine organism is destroyed, and therefore there is an 
interval when the glycerinated virus will still cause a typical ‘‘take,” 
but will contain comparatively few foreign micro-organisms. It is 
evident that if the glycerinated virus is used before this interval it 
has no advantage over the dry point, and if used after this interval it 
is inert. Therefore, from a theoretical view point gtycerinated virus 
should be freer from impurities if used just at the right time. Manu- 
facturers state that the}" usually glycerinate the virus from four to six 
weeks before putting it on the market. 
The dry points, on the contrary, may be sold as soon as made and, 
if kept in a cool place protected from the light, they probably remain 
viable a longer time than the glycerinated virus under similar condi- 
tions. It is well known that pus cocci and the other bacteria which 
frequently contaminate vaccine virus die quickly when dry. These 
same bacteria, however, live a comparatively long time in dry vaccine 
virus, probably on account of the protection of the albuminous matter 
in which they are imbedded. 
The glycerinated virus is made from the “pulp” that is scraped 
from the site of the eruption. This pulp consists of the inflammatory 
exudate and macerated cuticle. The mass is intimatelv ground with 
50 to 60 per cent of glycerin, then placed aside in a cool place for sev- 
eral weeks until the pyogenic cocci and other pathogenic organisms 
disappear. 
Until recently the dry points were always prepared by using the 
serum or “lymph” which exudes from the site of the eruption, after 
the crusts and epithelial layers have for the most part been removed. 
The sterile ivory points are then coated with this serum by means of a 
brush or the points are dipped directly into the exudate. This lymph 
is largely blood serum, mixed with inflammatory exudate. At present 
the dry points are mostly prepared from the glycerinated pulp. That 
is to say, the glycerinated virus, after it has stood a suflicient length of 
time to free itself of bacterial impurities, is dried upon ivory points. 
Sometimes the glycerinated virus is mixed with sterile blood serum in 
order to facilitate its drying and adhesion to the ivory point. 
