BOTANICAL SOCIETY OF LONDON. 
81 
between the different vegetable crystals. One may be con- 
vinced by reflecting that the largest crystals I have examined 
had 0. 11 of a line in length, a great many 0. 023, and all 
the intermediate sizes up to the infinitely small. My conclu- 
sions on this point are exactly in accordance with those of 
M. Raspail. (I have given drawings as exact as possible of 
the crystals found in the cellules of the following plants ; 
ficus bengalensis, Maranta zebrina, Musa paradisiaca, M. 
coccinea, Lucca gloriosa, Strelitzra regina, Papyrus antiquo- 
rum, Tritoma Uvaria, Aloe pulchra.) In these vegetables the 
crystals are separated, or at least free in the interior of the 
cellules, but they are often grouped and balanced between 
them as is seen in the several Rheums, in the Myriophyllum 
spicatum, Herniaria glabra , Mercurialis perennis, Viburnum 
hint ana, Cactus pendulus, Caladium nymphcefolium. The che- 
mical examination of these bodies offers no less difficulty 
than the determination of their physical form. Buchner, 
Schubler, Saigey, De la Fosse, Ness d’Esenbeck, and Ras- 
pail, are the only persons who have occupied themselves 
with it; their bases are lime, magnesia, and sometimes, 
though seldom, silex. The carbonic, oxalic, phosphoric, and 
tartaric acids, are combined with them. The method I 
have adopted differs from that of Raspail ; I left the crys- 
talliferous tissue to concoct in weakened nitric acid, filtered 
it, and then treated it with ammonia. I gathered the white 
precipitate, which then formed itself, and warmed it upon 
a plate of platina. The effervescence proved to me the ex- 
istence of vegetable acid, which must be either tartaric or 
oxalic. The author adds in a casual manner some observa- 
tions on the vessels of the latex in conformity with a plate 
which accompanies his paper. This is the substance of it. 
These vessels described by Schultz and Meyen are quite dif- 
ferent to the vasa propria, as M. Mohl has proved; they 
contained a more mucilaginous juice, with a resinous or gum 
substance. The proper vessels form a part, thus to speak, 
of the vascular bundles, and probably perform a part in the 
transfer of the juices. The vessels of the latex, on the con- 
trary, never accompany the other vascular bundles. They 
are constantly separated by cellular tissue, and develop them- 
selves by anastomosin, with several cellules placed end to 
end. They appeared to me to belong to the cellular rather 
than the vascular system. In one of the figures the author 
has represented these newly formed vessels, such as those he 
had observed in the pith of the Ficus bengalensis ; these are 
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