4 
442 Scientific Intelligence. 
aor cell. He adverted to the several theories of cell meoeee st 
said that in the last mentioned plant, in the development of the 
a bular terminal cells, ~* division of the permanent cell wall followed 
the division * the cell contents. In conclusion, he observed, that these 
matters would be more ful ee of hereafter, in a memoir whe, ¢ 
he meee fcona on the 
n Infusoria on nn Te i by Dr. H. 1. peu Ae 
roe of Arts and Sciences, Boston, Dec., 1849, p. 183.)—Dr. H. HL 
Bowditch gave the result of the microscopic ie 8 of the accu- 
mulations on the tenth: of healthy persons, near the gums, in forty-nine 
individuals, most o om were very particular in their care of the 
teeth. Aieosiaples a vegetable products were found in every in- 
stance except two. In those cases the brush was used three times a 
sk and especially of tobacco, by which — seemed to be in no 
wise incommoded. Soap-suds and the chlorine tooth-wash ave 
destroy them. 
IV. Astronomy. ooo 
its return is not yet to be teeiees of, Mr. J 
in a letter to the Editor of the London Times, dated March 
that Mr. J. T. Barber of Etwell, has computed the effect of the pertu 
bations due chiefly to Jupiter's attraction wee the last revolution. — 
Mr. B. finds that ** between the years 1556 and 1592, the united atirac- — 
tion of Jupiter and Saturn would diminish the period 263 days, but that 
between 1592 and 1806, it would be increased by the action of Jupiter 
alone no less than 751 days, so that a retardation of 488 days must take 
place. How much longer Saturn, Urn ald Neptune may detain it 
ae 
of 1851, and that on the supposition “ - is within four or five mo 
of its return to perihelion, the region e heavens about the come 
tion Hydra should at this time be pumcakesty examine 
