94 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
power of organisms takes place, after repeated sub-cultivation in 
nutrient gelatin. 
Fermentation of Bacillus coli communis.* — Dr. Y. Seruel reports 
that this bacillus is developed, in solutions containing glucose, as well 
when the supply of air is shut off as when there is an uninterrupted 
supply of it. However, in the latter case spores are more abundantly 
formed, and the decomposition of the sugar is more complete. The 
difference may be explained as due to the accumulation of carbonic acid. 
Acids formed in fermentation are not derived from one another, but 
arise independently. Acetic and lactic acids are probably residual 
formations, and as they are not attacked to any extent, they accumulate 
in the cultivations. Formic acid is, in all probability, produced in much 
greater quantities than one would suppose from the analysis ; it is 
decomposed in proportion to its production, and furnishes hydrogen 
and carbonic acid. The proportional relation between acetic and lactic 
acids is the same, whether the cultures are aerated or not ; and as the 
relation of these acids to the sugar consumed is also independent of 
conditions of aeration, we may suppose that the destruction of glucose 
obeys the same laws in the presence as in the absence of oxygen. 
Products of Staphylococcus pyogenes.f — MM. A. Rodet and 
J. Courmont find that certain pathogenic microbes are able to form 
simultaneously in the culture-medium distinct vaccinating and predis- 
posing substances. Staphylococcus yyogenes is an example of this. The 
vaccinating substance formed by this microbe is precipitated by alcohol, 
while the predisposing substance is dissolved. In filtered cultivations 
the effect of the vaccinating substance is completely masked by that of 
the predisposing substance ; heating for twenty-four hours at 55° is 
sufficient to make it appear. 
Destruction of Amoeboid Cells by Micro-organisms. \ — From ex- 
periments made on animals Dr. A. Ruffer concludes that the wandering 
cells of the lymphoid tissues of the alimentary canal have the power of 
wandering to the free surface of such tissues, and of taking into their 
interior micro-organisms and foreign matter (charcoal, &c.). There are 
two kinds of wandering cells in the lymphoid tissues of the alimentary 
canal, a , microphages (small mono- or multi-nucleated cells) ; h, macro- 
phages (large mono-nucleated cells). The macrophages are developed 
from the small mono-nucleated lymphocytes. Macrophages are able to 
swallow microphages (leucocytes) and to destroy and digest them. 
Micro-organisms are rapidly destroyed in the interior of the micro- and 
macrophages. Micro-organisms are never found lying free between 
the cells or in the blood-vessels and lymphatics. The destruction of 
micro-organisms taking place in the normal lymphoid tissues of the 
alimentary tract resembles, in all particulars, the destructive process 
following on the inoculation of pathogenic micro-organisms into resistant 
animals. 
It is further noted that the epithelioid cells of other lymphoid organs 
* La Cellule, vii. (1891) pp. 179-202. 
t Comptes Hendus, exiii. (1891) pp. 432-5. 
j Biit. Med. Journ., ii. (1890) pp. 491-3. 
