THE 
AMERICAN NATURALIST 
VoL. XXV. MARCH; 1891. 291. 
ARE ACQUIRED VARIATIONS INHERITED? 
BY HENRY FAIRFIELD OSBORN. 
Opening of a Discussion upon the Lamarckian Principle in Evolution; American 
Society of Naturalists, Boston, December 31st, 1891. 
AFE acquired characteristics inherited? We admit that indi- 
viduals inherit a certain constitution, and that definite varia- 
tions from this constitution are acquired during life-time, accord- 
ing to well-known laws. The question is: Are these definite 
acquired variations in any degree transmitted, or are the congenital 
variations in the constitution of the offspring independent of 
those which have been acquired by the parents ? 
PRESENT STATE OF THE QUESTION. 
Before opening this discussion let us draw up a balance sheet in 
biological philosophy for 1890, and determine exactly where we 
Stand in point of knowledge of natural causation. Fortunately 
Professor Huxley balanced the Evolution account in 1871' in his 
usual accurate and candid manner, enabling us to institute a 
comparison : 
“If I affirm that ‘ species have been evolved by variation® (a 
natural process, the laws of which are for the most part unknown), 
aided by the subordinate action of natural selection,’ it seems to 
me that I enunciate a proposition which constitutes the very pith 
3 * Critiques and Addresses,” p. Contemporary Review, 1871. This passage. 
‘s Practically a résumé of the the articlelentited * Mr. Darwin's Critics,” in which it occurs 
+ Hatading under this head hereditary transmission. 
E 
