NOTES. 369 
‘4 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. Wyv1LLe THomson. The recent experiments of Robert Hamilton 
tend to prove the existence, in every highly developed organism, of two 
lives: a life resident in every atom of the structure, however complex, and 
another life for which we fail to find an expression. But the latter is the 
life which keeps together the structure as a whole: it is the life that selects 
the nutrition best suited to its individual self; it is the life that has to do 
with the continuation of the species; lastly, it is the life to which the mo- 
lecular lives, which make up the structure, are subordinated; and when this 
nameless life departs, these myriad lives, no longer co-operating, start on an 
independent course. 
18 There was a time in owr 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-consideration. 
16 The vegetable cell has usually two concentric coverings: cell-wall and 
primordial utricle. In animal cells the former is wanting, the membrane 
representing the utricle. As a general fact, animal cells are smaller than 
vegetable cells. 
‘7 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 than 
the shells scattered in orderly lines along the sea-beach are the instruments 
by which the gravitation-foree 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. 
18 The white fibres are inelastic, and from gp3p55 tO aqghoo Of an inch in 
diameter. They are best seen in the tendons. The yellow fibres are elastic, 
curled at the ends, very long, and from gz}p5 tO ap'oo Of an inch in diam- 
eter. They are shown in the hinge-ligament of an Oyster. Connective tis- 
sue appears areolar, i. e., shows interspaces, only under the microscope. 
19 Certain bones, as €hose of the face and forehead, are preceded by mem- 
branes instead of cartilage. 
20 In the heart, the muscular fibres are striated, yet involuntary ; but the 
sarcolemma is wanting. 
21 Other names are medullary sheath and white substance of Schwann. 
22 We may, however, infer that the animal functions are not absolutely 
essential to the vegetative, from the facts that plants digest without mus- 
cles or nerves, and that nutrition takes place in the embryo long before the 
nerves have been developed. 
23 This is not strictly true, for the Elm and Oak, the Trout and Alligator, 
do reach a maximum size. 
24 The suctorial Insects always subsist upon one and the same kind of 
food. 
25 Scorpions and Spiders properly feed upon the juices of their victims 
after lacerating them with their claws; but fragments of Insects have been 
found in their stomachs. 
24 
