456 BACTERIA IN DIPHTHERIA. 
take from a paper upon the subject by Roux and Yersin (troisiéme 
mémoire, 1890). 
Found by Roux and Yersin in mucus from the pharynx and ton- 
sils of children—from forty-five children in Paris hospitals, suffering 
from various affections, not diphtheritic, fifteen times; from fifty- 
nine healthy children in a village school on the seaboard, twenty-six 
times. Of six children with a simple angina but two furnished cul- 
tures of this bacillus, while it was obtained in five out of seven cases 
of measles. 
Its characters are given as follows: 
‘* The colonies of the pseudo-diphtheritie bacillus, cultivated upon blood 
serum, are identical with the true diphtheria bacillus Ata temperature of 
33° to 85° multiplication is rapid, and it continues at the ordinary tempera- 
ture, although slowly. Under the microscope the appearance of the bacillus 
which forms these colonies is the same as that of Bacillus diphtheria. It 
stains readily with Loffler’s solution of methylene blue, and intensely by 
Gram’s method. Sometimes it colors uniformly, at others it appears granu- 
lar. It grows in alkaline bouillon, giving a deposit upon the walls of the 
vessel containing the culture, and in this medium often presents the inflated 
forms, pear-shaped, or club-shaped. It is destroyed in aliquid medium bya 
temperature of 58° C. maintained for ten minutes. All of these characters 
are common to the pseudo-diphtheritic bacillus and the true Bacillus diphthe- 
riz. Asa difference between them we may note that the pseudo diphtheritic 
bacillus is often shorter in colonies grown upon blood serum; thatitscultures 
in bouillon are more abundant; that they continue at a temperature of 20° to 
22°, at which the true bacillus grows very slowly. When we make a com- 
parison of cultures in bouillon they become acid and then alkaline, but the 
change occurs much sooner in the case of the pseudo-diphtheritic bacillus. 
Like the true bacillus, the pseudo diphtheritic grows in a vacuum, but less 
abundantly than the other. 
‘*Tnoculations into animals of cultures of this bacillus have never caused 
their death; but we may remark that in some experiments a notable edema 
has been produced in guinea-pigs at the point of inoculation, while in others 
there has been no local lesion. The most marked cedema resulted from cul- 
tures obtained from cases of measles. ; 
“ Do the facts which we have reported explain the question which occupies 
us? Can we conclude that there is a relation between the two bacilli? On 
the one side, the presence of the pseudo diphtheritic bacillusin the mouths of 
healthy persons, and of those who have anginas manifestly not diphtheritic, 
seems to be opposed to the idea of a relationship between them. On the 
other hand, when we consider that the non-virulent bacillus is very rare in 
fatal diphtheria, that itis more abundant in benign diphtheria, that it be- 
comes more common in severe cases as they progress towards recovery, and, 
finally, that they are more numerous in persons who have recently had 
diphtheria than in healthy persons, it is difficult to accept the idea that the 
two microbes are entirely distinct. The morphological differences which 
have been referred to are so slight that they prove nothing. The twomicro- 
organisms can only be distinguished by their action upon animals, but the 
difference of virulence does not at all correspond with the ditference of ori- 
gin. Asregards the form and the aspect of cultures, the true and false 
diphtheria bacilli differ less than virulent anthrax differs from avery attenu- 
ated anthrax bacillus, which, however, originate from the same source, 
Besides, the sharp distinction which we make between the virulent and non- 
virulent bacilli is arbitrary; it depends upon the susceptibility of guinea- 
pigs. If we inoculate animals still more susceptible, there are pseudo diph- 
theritic bacilli which we must class as virulent; and if, on the contrary, we 
substitute rabbits for guinea pigs in_our experiments, there are diphtheritic 
bacilli which we must call pseudo-diphtheritic. In our experiments we do 
