THE PHOSPHORESCENCE OE THE SEA. 
289 
ism, in those tissues which of all others maintain the greatest 
amount of activity, and dining then* most energetic action, 
could bear any relation to the physico-chemical forces which 
we bring into play in our laboratories ? How indeed can such 
a phenomenon be regarded otherwise than as the result of a 
vital act? 
This was my view of the case ; and here I found myself at 
one with Ehrenberg ; but I had gone farther than he had done, 
for I had satisfied myself that the seat of the phenomenon was in 
the muscular tissue, and was closely related to its contraction. 
These two entirely novel and unexpected results, however, 
needed verification by experiments on other animals, and I 
eagerly availed myself of the opportunity presented by the 
Noctilucao of the port of Boulogne to subject my opinions to 
a fresh test. The very important part which they play in 
“ general phosphorescence,” that is to say, in the phenomenon 
on its grandest scale, gave a special interest and importance to 
their study ; whilst the infinitude of these animalcuhe, and even 
their minute proportions, afford to the experimentalist greater 
facihties than any that I had previously possessed. 
In the first place, however, it was necessary to become 
intimately acquainted with the organization of the Noctilucie 
themselves ; and the results of this twofold study now remain to 
be described. 
4. The Noctiltjc.® and their Phosphorescence. 
The Noctilucie ( Noctiluca , Surriray; Mammaria, Ehrenberg) 
are, as we have already stated, microscopical animalcule bearing 
a pretty general resemblance to little melons deeply indented at 
one end. 
Hear this depression there is fixed an appendage, which the 
animalcule moves slowly to and fro, swaying it from right to 
left (see Figs. 1 and 2, a, b.). The body is so completely 
transparent as to admit of its structure being studied in its 
minutest details. It is inclosed by two hyaline membranes, 
representing the dermis and epidermis .* Near the appendage 
these membranes present a minute orifice, which serves as the 
outlet from a little mass of pellucid, homogeneous, and finely- 
granulated substance, which is prolonged into the internal part 
of the body. From this mass, which forms as it were a centre, 
there radiate in every direction a number of rhizopodic f exten- 
sions, which become more and more ramified as they proceed, 
and of which the ultimate indefinitely multiplied ramifications 
* The names given by physiologists to two coats of the skin. 
t The reader will recollect that we had to employ this expression in treat- 
ing of Amoeba, &c. (of the Rhizopoda, in fact), in the articles on the “ Lowest 
forms of Life,” Nos. I. & II. of this Journal. 
