1890 .] 
43 
[Jeffries. 
here comes in Lamarck’s belief in spontaneous generation, a doc- 
trine quite generally held during the early part of the century. 
The descendant of the more recently spontaneously generated 
forms giving the various lower stages in the series. 
Lamarck saw that this serial order was only partly followed and 
that here and there along the line changes and excursions in other 
directions came in. These he explained by his second law. Bec- 
ognizing that the physical geography of the globe was slowly but 
steadily changing, Lamarck formulated as follows : 
Each permanent slight change in the conditions of life of an an- 
imal may produce a real change in the needs of the animal. 
Each change in the needs of an animal necessitates other ac- 
tions to satisfy the needs, that is, other habits. 
“ Every new requirement, necessitating new actions to satisfy 
it, demands of the animal experiencing it (the requirement) , either 
the more frequent employment of some of its parts of which for- 
merly it made less use, which develops and increases it (the part) 
considerably ; or the employment of new parts which the new needs 
produce insensibly by the efforts of its (the animal’s) internal 4 sen- 
timent.’ 
Plants having no wants, according to Lamarck’s meaning, are 
held subject to their surroundings, as moisture and temperature, 
which, altering nutrition, slowly produce changes in the form and 
proportion of the parts. 
Lamarck’s first idea of an inherent law by which life is forced to 
advance is, of course, beyond the reach of demonstration, by its 
nature cannot be proved. It is allied to Spencer’s theories of ev- 
olution and the steady progress from the simple to the complex and 
seems to be the centre around which the Neolamarckians cluster. 
That such a progression, evolution, has taken place, there is no 
doubt ; all the branches of biology show it. But the existence of 
progression does not make it a law inherent in life. Such progres- 
sion can be explained by Darwinistic views or indeed by Lamarck’s 
other laws. The survival of the best adapted or the constant 
change with changed habit and surrounding is sufficient. 
Spontaneous generation being denied, the presence of so many 
simple forms is impossible of explanation if an inherent law of 
1 Sentiment is here used as indicating animal vital force rather than implying mind 
as in the usual use of the word, yet has some connection with habit as shown by the 
context. The word does not seem susceptible of a definite interpretation. 
