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THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[April 27, 1872. 
through thej dark ages, or to put it more correctly, the 
sponge in those times continued to discharge the practical 
duties of the toilette , and no unpractical questions re¬ 
garding its nature seem ever to have been asked. With 
the revival of learning in the sixteenth century, how¬ 
ever, the question was once more raised; the tide of 
scientific opinion set in strongly against Aristotle’s view, 
nnd the sponges were now placed by general consent 
among plants, and even characterized as the most im¬ 
perfect of their class. This remained the prevalent 
opinion dowm to modern times; thus we find Linnasus, 
in an early edition of his ‘Systema Naturae,’ arranging 
the sponges among the cryptogamous algae. About this 
time, however, Ellis and others succeeded in demonstra¬ 
ting the animal nature of zoophytes in general; again 
the views of the ancient writers were adopted, and in the 
twelfth edition of his great work, Linnaeus arranges 
the sponges among animal zoophytes. This opinion has, 
since that time, been the prevalent one ; while, since the 
publication in the Edinburgh ‘ Philosophical Journal,’ 
■of Dr. Grant’s investigations on the structure and func¬ 
tions of the sponge, it may he said to have become almost 
universal. Regarding the sponge, then, as belonging to 
the Protozoa—the lowest of the animal sub-kingdoms 
—let us observe how it plays its humble part in the 
economy of nature. 
The article known to commerce as the sponge, and 
which consists for the most part of a mass of delicate 
horny fibres interlaced with each other so as to form a 
rude sort of net-work, though it belongs to, yet does not 
•constitute the animal. It is merely a framework on 
which the living part is supported, and corresponding 
somewhat to the skeleton of the higher animals. Those 
horny fibres are so arranged as to form regular canals, 
which permeate the sponge in every direction, and open 
•on its surface in what zoologists term pores and oscula. 
The name of pores is given to the numberless small 
openings, while that of oscula is applied to those larger 
apertures which occur at rarer intervals on the surface 
of-the sponge. It will afterwards be seen that the pom 
and oscula have very important, though entirely different 
functions to perform. In many of the sponges also, 
little needle-like bodies known as spicules are found 
scattered through the mass. These can be most readily 
obtained by burning a piece of sponge, when they are 
left behind, and from the variety of fantastic shapes which 
they assume, form beautiful microscopic objects. Their 
presence, however, in any sponge is fatal to its value as 
an article of commerce. In the living state every fibre 
of the horny framework is covered over with a coating 
of gelatinous matter of a brownish-yellow colour, and 
in other respects somewhat resembling the white of egg. 
This is the substance known as protoplasm, and which 
Professor Huxley regards as the physical basis of life. 
As living sponge is but an immense aggregation of 
minute bodies of this protoplasm, it may be well to 
notice some of the results of recent investigation on this 
substance, and specially as regards its modes of occurrence 
in nature. It is a true living fluid, for when allowed to 
escape from the cell in which it is confined, it moves 
about and gives all the signs of possessing life. It 
occurs in both the A T egetable and animal kingdoms, 
existing in the former as the inner wall or primordial 
utricle, which is essentially the vital portion of every 
cell. In the latter it forms the most important con¬ 
stituent of the blood. Examine a drop of blood under 
the microscope, and it will be seen to consist of certain 
"bodies known as red and colourless corpuscles respec¬ 
tively, floating in a colourless fluid. Separate a red cor¬ 
puscle from its fellows, and it makes no motion; it 
passively assumes whatever shape you may impress upon 
it. Then place a single colourless corpuscle under the 
microscope, and, unlike the former, it will be seen to be 
ever changing its form, like a very Proteus. These 
colourless corpuscles consist of pure protoplasm. But 
this substance, which thus seems to carry on a subor¬ 
dinate^ independent life in the liquid element of our 
blood, is also found leading an entirely independent 
existence outside, not only in the aggregated form as in 
the sponge, but also as a separate solitary creature in the 
Amoeba. This creature is found attached to vegetabl 3 
growths in stagnant waters, and when looked at through 
the microscope behaves exactly as did the colourless cor¬ 
puscle in the blood, or the protoplasm of the inner wall ot 
the cell. It exhibits a constantly changing shape and 
has thus earned the name of Amoeba, from a Greek woi d 
signifying change. This creature has been the subj :ct 
of much and minute investigation, and yet no trace has 
been detected of what can properly be termed organized 
structure. It has no mouth, no gullet, no stomach and 
no intestine, and yet it gets hungry and eats; it gr s, 
and therefore it must digest. How then is the work of 
nutrition which we always associate with the possession 
of the above organs performed in a creature apparently 
so structureless as the Amceba ? Simply by its becom¬ 
ing for the time being, all mouth, then all stomach, and 
lastly all intestine. When the Amoeba finds itself in 
the neighbourhood of something fit for food, it brings 
itself into contact with it, and then no matter at what 
part of its body this contact takes place, there it opens up, 
—an extemporized mouth is formed, and its victim, some¬ 
times larger than itself, is gradually swallowed. Its 
food being thus engulfed, the creature now takes upon 
itself the duties of a stomacb, and the foreign body is 
gradually dissolved, until the entire soluble portion is 
abstracted; the insoluble remnant has now to be dealt 
with, and the Amoeba by virtue of a certain power of 
contraction which it is believed to possess, assumes the 
functions of an intestine, presses the effete matter from 
its interior towards its surface, when the animal again 
opens up and allows such matter to escape. But to 
return to our sponge; it has alx-eady been said that the 
gelatinous substance lining its canals is protoplasm. 
Any one may satisfy himself upon this point by getting 
a piece of living sponge from the Edinburgh and Glasgow 
canal, where the Spougilla jlmiatilis abounds. Taking a 
thin section of this and placing it under the microscope, 
the canals will then be seen to be filled with a fleshy 
substance made up of a number of little bodies. Isolate 
one of these, and it will be found to exhibit phenomena 
in every way similar to what has just been described as 
belonging to the Amoeba. Living sponge is thus an 
assemblage of amoeba-like protoplasms supported on a 
network of delicate fibres. Unlike those creatures, 
however, the protoplasms of the sponge are fixed, the 
entire colony remaining permanently rooted ; and being 
thus unable to go in search of food, they are solely 
dependent for their subsistence on the nutritious par¬ 
ticles that may happen to come within their reach; and 
this bring us to consider the functions of the pores and 
oscula on the surface of the sponge. Dr. Grant, after 
long-continued observations, discovered that there was 
a constant flow of water into the smaller openings or 
pores, and that there was as regular an outflow of water 
from the larger apertures or oscula. He also found that 
the water from the oscula, had in its course through the 
sponge, been deprived of its oxygen and of its nutritious 
ingredients; while, on the other hand, it had become 
charged with the effete materials of digestion. It was 
thus shown that, by some means or other, water laden 
with nutritive matter was made to enter by the pores, and 
that passing along the canals, it surrendered its valuable 
contents to the little protoplasms arranged along the 
sides; that sweeping on, it gathered up the effete matter 
constantly being given off, and then entering the wider 
passages, its course got turned, and now moving towards 
the surface was at last ejected from the oscula. The 
means by which these opposite currents are produced 
has been the subject of much controversy, but Dr. Grant 
has shown that in many cases at least they are produced 
by the action of vibratile cilia. These cilia are minute 
hair-like bodies found on certain parts of all animals, 
