SCIENTIEIC SUMMARY. 
107 
numerous, were exceedingly active. From this period (July 29) to August, 
monads were the only things to he seen, and they were few in number. On 
comparing the air of Sologne, which is a marshy district, with that of Eomain- 
ville, it was found that the former contained both microphytes and microzoa 
in much larger proportions than the latter. Associating this fact with the 
order of disappearance of the different forms of existence which he observed. 
Dr. Lemaire states that in his opmion “ there is a similar state of things in 
both aerial and terrestrial worlds. The plants serve as food for the animal- 
cules, when the former are consumed, then the smaller infusoria are eaten by 
the monads ; finally, the latter devour each other, the strongest alone surviving 
in virtue of the laws of the ‘ struggle, for life.^ What confirms this view is the 
fact, that in the vapour collected at Sologne, which was rich in microphytes, 
the bacteria and vibrions lived for fifteen days, whilst in that collected at 
Eomainville, in which there were few microphytes, they did not live for more 
than three.” However interesting these researches of Dr. Lemaire may be, 
there is stiU the question. Do bacteria or vibrions belong to the animal king- 
dom ? Till this is answered, the latter portion of his conclusion must be 
received with considerable distrust. 
Difference between Quercus Sessili-flora and Q. Pedunculata. — Some 
botanists are of opinion that the distinction between these two species of 
oak is more imaginary than real, but the study of the subject by Dr. Heinrich 
Mohl leads to an opposite inference. Moreover, as the structures upon 
which he bases his separation of the species are to be found whilst the plants 
are in leaf, an additional interest lends itself to the question. The bud of 
Q. Sessili-flora, says Dr. Mohl, tapers from below upwards, and is traversed 
by five well-marked longitudinal ridges. The bud scales are arranged in 
spiral cycles, the direction of which is very oblique, so that the successive 
scales of the same series only overlap one another to a slight extent at the 
base, but each scale covers over the lower half of the one placed immediately 
above it, in the adjacent cycle. The bud of Q. Pedunculata, on the other 
hand, is shorter, broadly ovate, less acutely pointed, its scales are strongly 
developed, and apparently irregularly distributed in four widely-separated 
spiral ranks, so that the half of each scale is uncovered, although the succes- 
sive scales of the same series frequently overlap one another at the base to 
the extent of half their surface. The leaf affords even more definite 
characters, that of Q. Sessili-flora being lobed at the base, whilst that of 
Q Pedunculata is simply wavy. — Vide review of Dr. Mohl’s Morphologische 
Untersuchungenuher die Eiche, in Journal of Botany for July. 
Gases exhaled by Fruits. — This is a subject which has not been so carefully 
considered as it deserves. M. Cahours, who has already investigated the 
respiration of leaves and flowers, has arrived at the conclusion that the green 
parts of plants are not the only structures which have the power of breathing. 
He has endeavoured to study (1) the proportion of gases contained in the 
parenchyma of the pericarp, and their composition ; (2) the action of fruit 
upon the pure oxygen and atmospheric air ; and (3) the action upon the 
same gases of each of the envelopes of the fruit, and that of the fleshy part 
also, when it exists. He finds that apples, oranges, and citrons, placed under 
bell-jars containmg oxygen, or this gas mixed with nitrogen, consumed oxygen 
and evolved carbonic acid, the proportions being gneater in diffused light than 
