with some Notices of American Diatome. — 123 
mals or vegetables. © On burning a great ae of Fragillaria pecti- 
nalis, an animal smell. was noticed. Such a smell would, however, be a 
very indefinite character, for various other Algw produce a similar odor 
on their being burnt to acoal. After the burning of the Fr pec- 
tinalis, and various other beings of the same kind, Brébisson found sili- 
ceous envelope surrounding . them. in a very perfect state, and precisely 
similar to those exhibited by the fossil Diatome, discovered by C. Fis- 
cher in the peat-bog near Franzensbad, and hick led to those beautiful 
observations that priate f= made, known o on n this se eeae in the course of 
discovered, only those beings are to be-understood, whid 1 cae as has 
been previously shown, receive as plants. The occurrence in a fossil 
slate of these minute microscopical plants, is caused by the hard siliceous 
envelop, which resists all destroying influences. Kiitzing’s discovery, that 
the envelop of the Bacillarie consists of silica, which was mentioned in 
our first year’ ’s report, has, by this circumstance, been rendered more im- 
portant. If we observe the same minute plants in the living state, it often 
happens, that amongst them some dead ones occur, which exhibit that 
perfectly transparent and colorless siliceous envelop ; it is therefore proved, 
that a great mass of such siliceous envelops might also be produced by 
the decomposition of the plants, or in the moist way, and also that the 
mountain masses, which consist more or less of such siliceous envelops, 
might not always be regarded as being produced by the action of heat at 
the bottom of the sea.t Brébisson tries to bring the Diatome into two 
divisions, viz. the proper Diatome, which exhibit a siliceous envelop, 
and the Desmidie, which are without a siliceous coating, and en ntirely 
reducible to carbon. In the more perfect plants, the epidermis of which 
is penetrated by a siliceous envelop, it would at least be Heroes to 
make such divisions; in this Gase , however, they may be of some 
“In a recent memoir, Mohl Sus again declared himself against ia ani- 
mal hature of the Bacillaria.. *T admit, says he, ‘that the doubt which 
was raised respecting their. vegetable nature is not yet removed ; their 
animal ‘nature, however , has been as little proved, and we find evident 
transitions from them pa vegetables.’ ”—lLond. and a Phil. Mag., Oct. 
o—390. 
1837, p. 38 
* Vide on Fossil Infusoria, Wicgmaae’ s Archiv, 1836, p. 333. A translation of 
Ehrenberg’ s two papers on this subject is given entire and with engravings in the 
Scientific Memoirs, Vol. 1, p. 400—W, F. 3 have not had an npaetipgd to see . 
either of these work . W. B. / 
t Ehrenberg’s opinion is, that these masses owe their origin to the ie of vol- 
canic heat on the bottom of the sea. Vide Scientific Memoirs, Vol. I, p. 4 
