382 
NOTES. 
4 This twofold division is arbitrary. No essential distinction, founded on 
the nature of the elements concerned, or the laws of their combination, can 
be made; and so many so-called organic substances, as urea, ammonia, alco¬ 
hol, tartaric and oxalic acids, alizarine, and glucose, have been prepared by 
inorganic methods, that the boundary-line is daily becoming fainter, and may 
in time vanish altogether. We would here utter our protest against the in¬ 
troduction of any more terms like inorganic, invertebrate , acephalous , etc., 
which express no qualities. 
5 Even the works of nearly all animals proceed in curves. 
6 London Quarterly Review , January, 1869, p. 142. It is true of any great 
primary group of animals, as of a tree, that it is much more easy to define 
the summit than the base. 
7 De Bary on “Mvxomycetse;” Darwin on “Insectivorous Plants.” 
8 “ There are certain phenomena, even among the higher plants, connected 
with the habits of climbing plants and with the functions of fertilization, 
which it is very difficult to explain without admitting some low form of a 
general harmonizing and regulating function, comparable to such an obscure 
manifestation of reflex nervous action as we have in Sponges and in other 
animals in which a distinct nervous system is absent.”—Prof. Wyville 
Thomson’s Introductory Lecture at Edinburgh . 
9 “ If nature had endowed us with microscopic powers of vision, and the 
integuments of plants had been rendered perfectly transparent to our eyes, 
the vegetable world would present a very different aspect from the apparent 
immobility and repose in which it is now manifested to our senses.”— Hum¬ 
boldt’s Cosmos , i., 341. 
10 See Gray’s “Structural Botany,” Sixth ed., Introduction; also Rolles- 
ton’s “Forms of Animal Life,” Introduction. 
11 “Life has been called the vital force, and it has been suggested that it 
may be found to belong to the same category as the convertible forces, heat 
and light. Life seems, however, to be more a property of matter in a certain 
state of combination than a force. It does no work, in the ordinary sense.” 
—Prof. Wyville Thomson. 
12 There was a time in our history when a single membrane discharged 
all the functions of life-—digesting, respiring, secreting. The separation 
of a heart, lung, stomach, liver, etc., for special duty was an after-considera¬ 
tion. 
13 The vegetable cell usually consists of a cell-wall surrounding the pri¬ 
mordial utricle, or protoplasmic sac. In animal cells the former, though often 
present, is usually not easily seen. As a general fact, animal cells are 
smaller than vegetable cells. 
14 Cells are not the sources of life, as once thought, but are the products 
of protoplasm. “ They are no more the producers of vital phenomena thar. 
the sheila scattered in orderly lines along the sea-beach are the instruments 
by which the gravitation - force of the moon acts upon the ocean. Like 
these, the cells mark only where the vital tides have been and how they 
have acted.”—Prof. Huxley. 
15 Many of the bones of the skull are preceded by membrane—hence called 
membrane-bones. 
