ON SPONGES. 
303 
by polypes^ but are^ as Ellis bad sliown_, animals of a peculiar 
kind_, destitute of any sensible motion. The surface of the 
sponge mass is covered with small pores^ which imbibe water ; 
this circulates in a continuous current by means of internal 
canals^ and is driven out with considerable force through the 
larger orifices or Oscula, The water entering by the pores is 
pure and untainted^ that which is driven ofi* is mixed with 
opaque feculent granules. Dr. Grant having put a small brailch 
of a common species of living sponge with some sea- water 
into a watch-glass^ and placed it under a microscope^ thus 
describes the appearance he then witnessed : — 
On moving the watch-glass, so as to bring one of the apertures on the side 
of the sponge fully into view, I beheld for the first time the splendid spec- 
tacle of this hving fountain vomiting forth, from a circular cavity, an im- 
petuous torrent of liquid matter, and hurling along, in rapid succession, 
opaque masses, which it strewed ever5W7here around. The beauty and 
novelty of such a scene in the animal kingdom long arrested my attention, 
but, after twenty-five mimites of constant observation, I was obliged to 
withdraw my eye, from fatigue, without having seen the torrent for one 
instant change its direction, or diminish in the slightest degree the rapidity 
of its course. 
The researches of Professor Grant were those that first gave 
to naturalists a correct idea of the inhalent and exhalent 
powers of these singular bodies, and the details given by him 
have had their accuracy confirmed by all who since then have 
studied the sponges in a living state. Hence it has been justly 
remarked that ‘‘ Dr. Grant has, in truth, proved himself to 
have been, in regard to the aqueous circulation in the sponge, 
what Harvey was to that of the blood of the higher classes of 
animal life, the first to discover and to publish the true mode 
of the circulation of the water in the animal."’^* 
MM. Audouin and Milne Edwards, after an attentive study 
of the sponges indigenous to the shores of France, confirm 
Dr. GranPs statements relative to these singular productions, 
which, to use the words of Dr. Johnston, certainly possess an 
animal life,^'’ — vivent d^une vie tout animale,^"’ — but to which, 
he says,t the anatomist may be tempted to refuse animality, 
since he cannot distinguish in them any organ by which it is 
characterized.'’"’ The names of distinguished natm^alists, both 
Continental and British, henceforward appear, as giving in their 
adhesionto the view of the animality of sponges. But some whose 
scruples are entitled to respectful consideration still held back. 
-x- Monograph of the British Spongiadse.” Bowerbank. Yol. i. p. 116. 
Bay Society, 1864. 
t Preface to “ British Sponges,” p. 57. 
