THE 
NEW PHYTOhOGIST. 
Vol. 2, No. 9. 
November 24TH, 1903. 
ON STIMULUS AND MECHANISM AS FACTORS 
IN ORGANISATION. 1 
By J. Bretland Farmer, F.R.S. 
SUPPOSE it may be taken for granted that in the study of 
plants, as in other sciences, the ultimate aim of all enquiry is 
to establish a clear connection between cause and effect. The 
earlier stages in the enquiry consist in describing and classifying 
the effects or phenomena themselves, but there are probably few 
investigators who remain content with these efforts alone. In 
order to gain a wide comprehension of the phenomena it is 
essential that the factors that underly them shall be convertible 
into chemical and physical expressions, since in this way only is 
there any apparent chance of penetrating the temple in which the 
secrets of life are so securely guarded, 
It must be confessed that most of the attempts in this direction 
have met with but scant measure of success. The hypotheses have 
often turned out to be erroneous and the theories destitute of any 
solid basis. But this circumstance does not affect the essence of 
the enquiry, nor indeed even its method. It is—or ought to be— 
a truism that the value of any hypothesis stands not in a necessarily 
direct relation to its final correctness, but rather depends upon the 
extent to which it welds together, even temporarily, cognate facts 
so as to suggest new lines of enquiry. No one doubts the value of 
the atomic theory, though of late there have not been wanting 
numerous assailants of this fundamental doctrine; and although 
perhaps few naturalists would be prepared to assert to day with the 
same confidence that would have shown twenty years ago, that we 
have got to the bottom of the question as to the origin of species, 
nevertheless, history will assuredly preserve the great Darwinian 
Theory as one of the most precious landmarks in the advance of 
science and philosophy, whether it should ultimately turn out that 
1 A lecture delivered before Section K of the British Association, 
Southport, 1903. 
