CHAP, v.] the Influence of the Knowledge of Cryptogams. \ 93 



most persevering labour not of one man only, but of whole 

 generations of observers and thinkers, nor did he apply him- 

 self with painful unremitting industry to the attainment of this 

 exalted aim. 



Soon after Schleiden's ' Grundziige ' first stirred the scientific 

 world, a man of a very different character of mind began to 

 address himself to the great task. This was CARL NAGELI, 

 whose researches from this time onwards laid the foundations 

 of knowledge in every department of botany. He showed what 

 points were the most immediately attainable, and aided in 

 perfecting the inductive method of enquiry and in advancing 

 the study of the history of development. He did not make 

 discoveries here and there by desultory efforts, but worked 

 with earnest endurance at every question which he took up till 

 he had arrived at a positive result ; and this was almost always 

 an enlargement of previous knowledge, and a new foundation on 

 which others might build, and a copious literature be developed. 



Nageli like others felt the necessity of first determining his 

 position with respect to the philosophical principles of the 

 investigation of nature, but he did not proceed to give a 

 general exposition of the inductive method as opposed to the 

 dogmatism of the idealistic school. He went straight to the 

 application of the laws of induction to the most general 

 problems of organic nature, and specially of vegetation. It 

 is easy to say that the task of natural science is simply to 

 deduce conceptions and laws from the facts of experience by 

 aid of exact observation. Many considerations present them- 

 selves as soon as the attempt is made to satisfy this demand ; 

 for it is not enough merely to accumulate individual facts, the 

 point to which the inductive enquiry is to lead must be kept 

 constantly and clearly before the mind. Nageli insisted that 

 it is only in this way that facts and observations have any 

 scientific value ; that the one important thing is to make every 

 single conception obtained by induction find its place in the 

 scheme of all the rest of our knowledge. With greater con- 

 o 



