HISTORICAL ACCOUNT OF EVOLUTION THEORY 19 
from Botany to Zoédlogy, without gaining the greatest admiration for 
his genius. Noone has been more misunderstood, or judged with more 
partiality by over or under praise. The stigma placed upon his writ- 
ings by Cuvier, who greeted every fresh edition of his words as.a 
‘nouvelle folie,’ and the disdainful illusions to him by Charles Darwin 
(the only writer of whom Darwin ever spoke in this tone) long placed 
him in the light of a purely extravagant, speculative thinker. Yet, 
as a fresh instance of the certainty with which men of science finally 
obtain recognition, it is gratifying to note the admiration which has 
been accorded to him in Germany by Haeckel and others, by his 
countrymen, and by a large school of American and English writers 
of the present day; to note, further, that his theory was finally taken 
up and defended by Charles Darwin himself, and that it forms the 
very heart of the system of Herbert Spencer.” 
Lamarck’s main theory of evolution was expressed by him in the 
form of his four ‘“‘laws”’: 
I. “Life, by its proper forces, continually tends to increase the 
volume of every body which possesses it, and to increase the size of its 
parts, up to a limit which brings it about.” 
II. “The production of a new organ in the animal body results 
from the supervention of a new want which continues to make itself 
felt, and a new movement which this want gives rise to and maintains.” 
Ill. “The development of organs and their powers of action are 
constantly in ratio to the employment of these organs.” 
IV. “Everything which has been acquired, impressed upon, or 
changed in the organization of individuals during the course of their 
life is preserved by generation and transmitted to new individuals 
which have descended from those which have undergone these 
changes. 
It is about the last ‘‘law”’ that the controversy rages, for it upholds 
the idea that acquired characters are inherited, now known as the 
“‘Lamarckian doctrine.” 
A somewhat more specific statement of Lamarck’s theory of 
evolution may be summed up in the following list of factors which he 
considered as playing an essential réle in evolution. 
1. “Favorable circumstances attending changes of environment, 
soil, food, temperature, etc., supposed to act directly in the case of 
plants, indirectly in the case of animals and man.” 
2. “Needs, new physical wants or necessities’ induced by the 
changed conditions of life. Lamarck believed that change of habits 
