1911.] On Variation and Adaptation in Bacteria. 555 
and find that further differentiation is possible by the use of various 
polyvalent alcohols and glucosides. 
Using these methods Holth and Jensen find, even in “closely similar ° 
conditions of disease,’ that the strains of streptococci present in different 
cases are different, and they ask the question whether these differences are 
really stable and fixed characters or are merely casual variations. Jensen 
states that Holth’s experiments (not yet published) lead to the conclusion 
that the differences are actually fixed, and that the organisms concerned are 
distinct and well-defined forms, but possessing similar pathogenetic action. 
A description of the methods which Holth has employed to prove the 
stability of the differences in question will be awaited with interest, since it 
is evident from the experiments described above that such observations need 
to be prolonged or the conditions of experiment sufficiently varied before 
definite conclusions can be safely drawn. 
One conclusion of great interest follows from the observation of these 
authors that closely similar conditions of disease may be associated with 
quite different strains of streptococci. It is that the differences brought out 
in carbohydrate, alcohol, and glucoside containing media are in no way 
closely related to the virulence and pathogenetic action of the streptococci 
examined. Accordingly no reliable inferences as regards these most 
important questions can legitimately be drawn from the results obtained in 
the media at present under discussion. The claim of Andrewes and Horder 
that the results so obtained were such as to enable one the better to form 
a prognosis and to initiate treatment therefore appears to lack sufficient 
evidence. 
In continuing his communication Jensen next proceeds to discuss a special 
streptococcal disease of horses, namely, strangles. After pointing out the 
fact that the course and pathology of this disease varies remarkably in 
different cases, he states that Holth, who has examined about 40 strains of 
streptococci from strangles of Danish, German, English, and Swedish origin, 
has by the use of a very large number of his test media definitely proved 
them all to be identical. And the constancy of the reactions thus found is 
not attributable to the residence of the organisms in the horse, since this 
animal harbours many other streptococci which present quite different series 
of reactions in the same media. 
It would appear, however, that the fact that organisms so completely 
identical as these are found to be in the test media are admitted to vary 
greatly in their pathogenicity in horses only shows again how small is the 
assistance to be looked for from this method of identification in dealing with 
the practical problems of disease. It is quite possible, and indeed even 
