170 LAMARCK, HIS LIFE AND WORK 
able. He prefers to think that nature is only a 
result, “whence, I suppose, and am glad to admit, 
a first cause, in a word, a supreme power which 
has given existence to nature, which has made it as 
a whole what it is.” 
As to the source of life in bodies endowed with it, 
he considers it a problem more difficult than to de- 
termine the course of the stars in space, or the size, 
masses, and movements of the planets belonging to 
our solar system ; but, however formidable the prob- 
lem, the difficulties are not insurmountable, as the 
phenomena are purely physical—z.e., essentially result- 
ing from acts of organization. 
After defining life, in the third chapter (beginning 
vol. ii.) he treats of the exciting cause of organic 
movements. This exciting cause is foreign to the 
body which it vivifies, and does not perish, like the 
latter. ‘This cause resides in invisible, subtile, 
expansive, ever-active fluids which penetrate or are 
incessantly developed in the bodies which they 
animate.”” These subtile fluids we should in these 
days regard as the physico-chemical agents, such as 
heat, light, electricity. 
What he says in the next two chapters as to the 
“orgasme”’ and irritability excited by the before- 
mentioned exciting cause may be regarded as a crude 
foreshadowing of the primary properties of proto- 
plasm, now regarded as the physical basis of life—z.e., 
contractility, irritability, and metabolism. In Chapter 
VI. Lamarck discusses direct or spontaneous genera- 
tion in the same way as in 1802. In the following 
paragraph we have foreshadowed the characteristic 
