524 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
disappeared. Asparagin is also converted into nitrite, but much more 
slowly, and sodium nitrite is gradually oxidised to nitrate through the 
agency of the microbes present in the cement. 
Leucocytes and Immunity to Arsenious Acid.* — Dr. Besredka’s 
third memoir deals with the part played by the leucocytes in the im- 
munisation against soluble arsenious acid. The chief points are that 
rabbits may be immunised against fatal doses of arsenious acid by 
accustoming the leucocytes thereto. This may be done by spreading 
a fatal dose over the whole day, or by injecting a small dose previously, 
or by combining the two methods. The serum of animals immunised 
by any one of the foregoing methods possesses preventive and antitoxic 
properties against a dose of arsenious acid fatal within forty-eight hours. 
Antiarsenin is in all probability a non-arsenical compound. 
The arsenic which is associated with the antiarsenin is not dialysable, 
and proceeds from the cells. The hypothesis of the neutralising action 
of antiarsenin, either partial or total, is in opposition to the facts. 
Antiarsenin acts upon the toxin through the intermediation of the 
leucocytes ; suppression of the latter paralyses the action of the anti- 
arsenin. 
Phagocytosis in the Pigeon.j — M. Dembinski finds that there is a 
marked difference between the phagocytic reactions of the pigeon to 
human and to avian tubercle. His experiments show that the difference 
between avian and human tubercle bacilli can be detected directly after 
inoculation by the cell reaction which is excited. If the tubercle 
bacillus be avian, phagocytosis is powerless to arrest the development 
of the disease ; for either the cells are unable to digest the englobed 
bacilli which thus preserve their vitality, or the number of bacilli incor- 
porated may be very small. If the bacilli be human, they are at once 
blockaded and rendered harmless by the numerous leucocytes, by the 
agglomeration of which giant-cells are formed, and thus are produced 
phagocytic protectors of a more powerful order than isolated leucocytes. 
Mechanism of Agglutination.}: — According to Dr. J. Bordet, the 
theories which would explain microbic agglutination by swelling and 
viscosity of membranes or cilia, conflict with numerous objections, and 
do not explain all the phenomena of agglutination. On similar grounds, 
the theory that regards agglutination as being due to the formation of 
a precipitate in the liquid may also be discarded. Now agglutination 
may affect very different elements (globules, casein, microbes) ; and for 
agglutination by serums only one explanation is admissible. It may be 
accepted that the agglutinins, by fixing on agglutinable elements, induce 
modifications in the molecular attractions which unite these elements 
either to one another or to the circumambient fluid. The whole pheno- 
menon of agglutination may be divided into two phases, the first of 
which may be produced experimentally without exciting the second. 
In the first the microbes, though scattered and far apart, come into con- 
tact with the agglutinin, which they fix. In the second, or period of 
agglutination properly so-called, the particles may present peculiarities 
* Ann. Inst. Pasteur, xiii. (1899) pp. 465-79. Cf. this Journal, ante , p. 320. 
t Tom. cit., pp. 426-39 (5 figs.). \ Tom. cit., pp. 225-50. 
