414 NOTICES OF THE MEETINGS [March 24, 
more than ever inapplicable to the organisms which required the mi- 
croscope to detect their existence. Recent researches had shewn that 
the motile tissues in animals were composed of the same substance 
that was found to be present in the cells of all plants, and which 
under the names of nucleus, cytoblast, primordial utricle, and endo- 
plast, had been recognised by all vegetable physiologists. This 
substance, composed of protein, was as actively motile in the plant as 
the animal. It was this substance which gave motility to the cells 
of Protococcus, the fibres of Oscillaria, the spores of various con- 
ferve and fungi, and probably also to all other movements observed 
amongst plants. 
When cilia were originally discovered as the agents of movement 
in infusoria, and upon the internal organs of higher animals, they 
were regarded as characteristic of animal life. These organs were 
now known to be present in the zoospores of various conferve, and 
were the active agents of movement in the Volvox globator, of whose 
vegetable nature there could be little doubt since the researches of 
Williamson and Busk. 
The possession of what were called eye-spots in doubtful organisms 
had been brought forward to decide the animality of these beings. 
Such eye-spots were present as red points in certain stages of the 
growth of Volvox, and other undoubtedly vegetable organisms, and 
according to Henfrey were due to the relation of the contents of the 
cell to light, and were in no way the agents of vision in the cells in 
which they are found. 
The definition of Aristotle, that animals possessed a mouth, whilst 
plants had none, had been recently revived ; and of all merely struc- 
tural characters, it was the one best suited to the purpose of the 
naturalist. Until recently the exceptions to this definition .were 
numerous; but since the botanist had claimed so large a number of 
mouthless infusoria, as the Diatomacee, Desmidee, and Volvocinee, 
it was more than ever applicable. There were, however, certain 
exceptions ; and these were found in the Foraminifera, the Difflugia, 
and other low organisms which had no permanent mouth. Some of 
these have the power of forming a temporary sac for the purposes 
of digestion. 
Chemistry had from time to time offered its aid to the naturalist. 
At one time the possession of cellulose by the vegetable kingdom 
was considered distinctive, and the ready application of iodine and 
sulphuric acid as the test of its presence rendered it an easily as- 
certainable diagnostic mark. It had, however, been recently detected 
by Smid in the Ascidian mollusca, by Thwaites in the dAcaride, and 
by Virchow in the brain and spleen of man. 
Another substance, chlorophyll, appeared at one time, to pronounce 
the presence of plants; but it had been found by Schulz in Hydra, 
Turbellaria, Vortex, Mesostomum, Stentor, Bursaria and other de- 
cidedly animal organisms. 
Starch was another vegetable product, easily detected by iodine, 
