Botany and Zoology. 127 
tainty, even with double that enlne power. When once their ex- 
istence on a slide is shown with a a power of 1500 to 1700 diameters, it is 
quite possible aharvAars age recognize the same object with a power of 
750,’ ’ ke. Hes u _can now have no doubt of ane fact. hee 
though the infusion itself be thoroughly boile “Tt seems clear 
pat either (1) the germs of Bacterium are capa able of resisting the boiling 
mperature in a fluid, or (2) that they are spontaneously generated, or 
(3) that they are not ‘ organisms’ atall. I was myself somewhat inclined 
to the latter rect concerning them at one time; but some researches in 
which I am now engaged have gone far to convince me that they are 
really minute focal: forms. The choice, Nests ps seems to remain 
between the other two conclusions. Upon these I will not venture a 
Positive opinion, but remark only, aor if it be true that ‘germs’ can re- 
sist the boiling temperature in fluid, then both parties in the controversy 
are working upon a false principle, ae neither M. Pouchet nor M. P. 
teur is likely at present to solve the problem of spontaneous gene’ n 
The decided conclusion as to the rganic chernctet of these B mga 
was reached through an examination of t ety the = object- ae 
cently iiatodet by Messrs. Powell and Tesla ; @ 
On the absorption and assimilation of sevice acid by pipe 
Mr. ‘Bovestreavct. has recently made some experiments on the absorp- 
tion and assimilation of carbonic acid by leaves exposed to sunlight. 
His results are thus summed up: 1. Leaves rahe to the sun in pure 
carbonic acid do not decompose this gas, or if they do, it is with exces- 
sive slowness, 2. Leaves exposed in a mixture of carbonic acid and 
atmospheric air rapidly ke Beet re former gas. Oxygen does not 
seem to interfere in the phenomenon. 3. Carbonic acid is rapidly de- 
composed by ~ when that gas is — with either hydrogen or 
Thus phosphorus placed in pure oxppeit do oes not i me luminous, and 
does not burn, or if it does, burns with excessive slowne Inam mixture 
of oxygen and atmospheric air, ee al ieee bas 1 rapidly ; it 
onic acid cabins the gas and e pies oxygen.— Reader. 
8. Classification of Polyps; by ‘A. E. Verrttt.—The following sabe 
divisions of the class of Polyps have been proposed by Prof. Verrill, in 
the Proceedings of the Essex Fstitute, vol. iv, p. 145. 
Orver I. Maprerorarta.—Polyps simple or compound with embry- 
onic or rudimentary basal or abactinal ion: which has no special func- 
tion unless for vegetative attachment while young. Actinal area well 
eared, form broadly expanded, having a tendency in | 
groups to become narrowed Toward the mouth. Tentacles simple con 
