6 64 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
avian tuberculosis, and that the two bacilli, so different in appear- 
ance, are merely varieties of the same species. By inserting in the 
peritoneal sac of fowls collodion bags filled with cultures of human 
tuberculosis, and removing these after an incubation of four months, the 
author succeeded in imparting to the human tubercle bacilli characters 
which are recognised as being distinctive of avian tuberculosis. 
The chief differences between the two varieties are that the cultures 
of human tuberculosis are dry, scaly, and difficult to dissociate, while 
those of avian tubercle are soft, greasy, wrinkled, and easily spread out. 
Avian tubercle bacilli still grow at 43°, a temperature at which human 
tubercle bacilli cannot be cultivated. It is almost impossible to inoculate 
fowls with mammalian tubercle ; on the other hand, certain mammals 
are refractory to avian tuberculosis, e. g. the dog. The guinea-pig re- 
sists subcutaneous inoculation, but succumbs to intraperitoneal, though 
the lesions it then presents are different’ from those excited by human 
tubercle. 
Permanence of the Infection of the Tubercle-bacteria.* * * § — From ex- 
periments on a variety of species of Leguminosse, Herren F. Nobbe and 
L. Hiltner find that in all cases the bacteria which infest the root-tubercles 
retain not only their vitality, but their activity, for twelve months ; and 
this power of infection is not confined to tubercles belonging to the same 
species, or even genus, of host-plant, as that from which the microbe was 
originally obtained. 
Influence of Filtration on Diphtheria Antitoxin.f — According to 
Dr. L. Cobbett, diphtheria serum loses in antitoxic power by transmis- 
sion through filters. This loss varies from practically nil to over 30 
per cent., and depends directly on the “ stopping ” power of the filter. 
Hence diphtheria antitoxin, when prepared in bulk, should be passed 
through an easy flowing filter, and the operation should be suspended as 
soon as there are indications of the apparatus getting blocked, and no 
attempt should be made to force the liquid through at a high pressure. 
Of course the antitoxic efficiency must be calculated after filtration. 
Aberrant Growth-forms in Streptococcus and Pneumococcus.^ — 
Dr. A. Stolz draws attention to atypical appearances and aberrant forms 
which occur in Streptococcus and Pneumococcus. In some preparations, 
large flask-shaped and bacillary forms are not uncommon ; and if the 
chains or collections be carefully observed, these will show not only 
great differences in the size and shape of the individuals, but also frequent 
departures from the normal division-direction. Thus, instead of Strepto- 
coccus forming long chains composed of individuals of the same size and 
shape, reproduction masses having resemblance to Staphylococcus, rosette 
collections, bifurcating lines, &c., will be found to be not unfrequent. 
Method of Action of Preventive Serum against Swine Erysi- 
pelas. § — M. F. Mesnil, who has investigated the method of action of 
preventive w serum of swine erysipelas, states that when rabbits are 
vaccinated by the Pasteurian method, it is possible to obtain an anti- 
* Landwirdsch. Yers.-Stat., 1898, p. 467. See Bot. Centralbl., 1898, Beih., p. G4. 
f Centralbl. Bakt. u. Far., l te Abt., xxiv. (189S) pp. 886-91, 415-19. 
X Tom. cit., pp. 337-48 (6 figs.). 
§ Ann. Inst. Fasteur, xii. (1898) pp. 481-500. 
