io6 
THOMPSON YATES LABORATORIES REPORT 
that at the time of examination some conjunctival sacs are absolutely free from 
organisms, but the frequency of the occurrence of the xerosis bacillus and its presence, 
or the presence of other organisms, after repeated examination makes the conclusion 
that the normal conjunctival sac is sterile only in a very small number of cases 
apparently inevitable. 
The list of organisms show that the pathogenic bacteria do not occur very 
frequently, and the experiments with them on animals demonstrate that they have to 
a certain extent lost their virulence. 
It seems, therefore, that although a conjunctiva is but rarely sterile, the 
organisms it usually contains would have little effect in prejudicing the result of an 
aseptic operation. 
Certain operations on the eye are performed in the upper quadrants, and, as 
Eyre 4 pointed out, the upper fornix conjunctivae seldom contains organisms, the 
frequent sterility of this part of the conjunctiva and the infrequent occurrence of 
pathogenic organisms explains why eye operations so rarely become septic. 
Staphylococcus aureus was isolated eight times — in six instances from children, 
and only two from adult sacs ; the latter were found to be considerably less pathogenic 
than some of those isolated from children's eyes. 
Streptococcus brevis was not found once in adults, the streptococcus longus 
only twice, and in one of the two was not pathogenic to mice. 
The frequent occurrence of both varieties of streptococcus in children's eyes 
was very striking, and in order to confirm the results twelve additional cases were 
examined ; in these streptococcus brevis occurred four times, streptococcus pyogenes 
longus twice. 
To produce quickly a quantity of streptococcus longus the following method 
was adopted : — Over a twenty-four hours' sub-culture on slant agar, sterile broth was 
poured sufficient to cover all the colonies, and incubated at 3 8° C. ; in one day each colony 
had grown out into the broth as a delicate villous-like prominence, with the position 
of the colony as a base ; further incubation produced more growth, and if the tube 
was kept perfectly motionless fairly long threads grew out into the broth ; from these 
growths very beautiful microscopical specimens of chains could be made. The 
slightest movement of the medium precipitated the mass to the bottom of the tube. 
In two cases a few transparent colonies were noticed, which consisted of oval 
cocci, morphologically similar to the pneumococcus ; they quickly died out, and it 
was not possible to study their life history. 
Staphylococcus epidermidis albus (Welch) was observed on forty-seven 
occasions. Randolph isolated it in eighty-five out of one hundred cases examined. 
The 'red bacillus' resembled in biological characters B. latericeus. On all 
media it formed a brilliant red growth ; on gelatine it grew abundantly, but did not 
liquefy the medium. 
