Jeffries. J 
44 
[May 7, 
progress exists in life. To-day, spontaneous generation is not ac- 
cepted. Certainly no atom of proof has ever been adduced in its 
favor ; yet it cannot be denied life must have begun once and un- 
der much the same conditions as at present exist, or it would have 
died at its birth. 
This law of advance, not distinctly formulated by Lamarck, can 
hardly find a place in science. 
Although no tendency to evolve can be accepted as inherent in 
life, there is nothing which precludes the idea that a change once 
induced may involve others and thus by the aggregated momen- 
tum of many changes the animal become subject to forces causing 
it to continue evolving regardless of outside changes. 
That changes in surroundings produce change in habits is self- 
evident. Our common rat and mouse and domestic animals have 
all changed their habits. That changes in habits with resultant 
change of use produce marked changes in the system of the indi- 
vidual is also well known. The legs of the postman, the arms of 
the blacksmith and the muscles of the thumb and index finger of 
the dentist are examples. With the play and pressure of the parts 
follow changes in the joints, for instance, the flexible fingers of the 
pianist. That disuse promptly brings atrophy every one who has 
worn a splint knows. 
But all these changes are or appear to be confined to the indi- 
vidual and not transmitted to the offspring. Here Lamarck fills 
the gap by demanding that both parents must be like developed 
and that the descendants for many generations must have like hab- 
its. Given an indefinite number of generations where male and 
female were blacksmiths, and, finally, the powerful arms would 
become engrafted on the young. Very likely, he might have thus 
explained the gorilla’s arms and man’s legs. 
But, proof ! cries the skeptic ; yet in the nature of things proof is 
not easily to be adduced. Man cannot keep any set of conditions 
for a sufficient length of time to allow of any reasonable hope of 
change ; for this years must become as days. 
Perhaps the best example of this law is that given by Darwin, 
namely, that the leg bones of domestic ducks are longer and heav- 
ier in proportion to the rest of the bird than in wild ducks. We 
do not, however, know if the stronger legs would continue for a 
time if the ducks diminished their use of them. Darwin’s text in 
explanation of the ostrich and other birds unable to fly is parallel 
