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with narrower turns in the wood of Firms picea. Broader spiral bands are 
observable in the outer wood-cells of the annual ring of conifers, and the 
striation is more sharply defined by application of nitric acid. When un- 
lignified, as in Apocynacece and Asclepiadacece , the iodine tests produce on 
the laminae the usual blue reaction.” 
Cryptoyamic Vegetation in the Egg of an Ostrich.— At a meeting of the 
Scientific Committee of the Royal Horticultural Society (March 4, 1874), 
the Rev. M. J. Berkeley called attention to the following communication 
made by Professor Panceri to the Institut Egyptien, at its meeting on 
December 13, on Cryptogamic vegetation found within the egg of an 
ostrich, which was interesting in connection with what he had himself 
brought before the committee on March 5 and 19, 1873. The egg had been 
given Professor Panceri at Cairo, and was still fresh, the air space having 
not even been formed. He soon, however, noticed the appearance of dark 
blotches within the shell, and having broken it open to ascertain the cause, 
he found that they were produced by the growth of minute fungi. Instances 
of a similar kind had already been studied by him, and he had communicated 
the results to the Botanical Congress held at Lugano in 1859. The Rev. 
M. J. Berkeley had found Cladosporium herbarum in the interior of a fowl’s 
egg. 
Passage of Gases through Colloid Membranes of Plants. — The experiments 
which have been made on this subject fully bear out those well-known 
experiments of Graham on the passage of gases through caoutchouc. M. 
Barthelemy says that the white spots on the Eegoniacece are merely elevations 
of the epiderm on a layer of nitrogen. The leaves of certain varieties, very 
thin on the living plant, are reduced, on fading during the winter in darkness, 
to the condition of a pellicle endued with elasticity, and representing almost 
nothing but the cuticular layers. It was these colloid membranes which 
served to repeat Graham’s experiment. Except in a few modifications of 
detail, he followed strictly the course of that illustrious physicist. In 
four experiments made with different membranes, he obtained the following 
results : — 
1st. 
2nd. 
3rd. 
4th. 
CO 2 
l h 
l h 
l h 
P 
N 
15 h 
13 h 40 m 
15 h 30“ 
14 h 
0 
6 h 
6 h 20“ 
7 h 
5 h 40* 
The experiments made under conditions of pressure, temperature, and 
moisture, which doubtless were not identical, yet agree sufficiently well 
with those of Graham, and allow us to conclude that the natural colloid 
surfaces of vegetables have for carbonic acid an admissive power which is 
thirteen to fifteen times as great as that of nitrogen, and six or seven times 
that of oxygen. Some days after he repeated the experiment with carbonic 
acid, perfectly dry, and found for its velocity compared with nitrogen 
numbers varying from nine to eleven ; it seems, then, that dry carbonic acid 
passes less rapidly than when moist. Replacing the vegetable film by 
caoutchouc, he obtained a similar result. The difference in the case of dry 
oxygen and nitrogen is less marked. He remarks, in conclusion, that these 
experiments prove the dialysis of carbonic acid through the cuticle of 
leaves, just as much as those of Dutrochet on membranes and aqueous, 
solutions prove endosmose by cellules. 
