720 Fluctuations 



large measure. Moreover, Knight pointed out 

 more than once that it is the amount of nourish- 

 ment, not the quality of the various factors, that 

 exercises the determinative influence. Nourish- 

 ment is to be taken in the widest sense of the 

 word, including all favorable and injurious ele- 

 ments. Light and temperature, soil and space, 

 water and salts are equally active, and it is the 

 harmonious cooperation of them all that rules 

 growth. 



We treated this important question at some 

 length, when dealing with the anomalies of the 

 opium-poppies, consisting of the conversion of 

 stamens into supernumerary pistils. The de- 

 pendency upon external influences which this 

 change exhibited is quite the same as that shown 

 by fluctuating variability at large. We inquired 

 into the influence of good and bad soil, of sun- 

 light and moisture and of other concurrent fac- 

 tors. Especial emphasis was laid upon the 

 great differences to which the various individ- 

 uals of the same lot may be exposed, if moisture 

 and manure differ on different portions of the 

 same bed in a way unavoidable even by the most 

 careful preparation. Some seeds germinate on 

 moist and rich spots, while their neighbors are 

 impeded by local dryness, or by distance from 

 manure. Some come to light on a sunny day, 

 and increase their first leaves rapidly, while on 



