LIFE AND WRITINGS OF M. DE MARTIUS. 43 



organography ; the physiologist ought to have some acquaintance with 

 chemistry, pharmacy, agriculture, horticulture, and botany ; the micro- 

 scopist may certainly dispense with much, but not with some experi- 

 ence in optical instruments, nor with the power to verify the name of 

 a plant. The example of some men goes to prove that for even the 

 most restricted branches of study extensive information is highly valu- 

 able; for M. Tulasne, who is the ablest microscopist of the present 

 day, is a Doctor of Laws, and the erudite author of several botanical 

 monographs of flowering plants. Let people say what they will, and 

 despite the present disposition to adhere to minutiae, the essential ob- 

 ject of Botany is and always will be to know plants ; and if a thing, to 

 be understood, must be studied all round, it is needful to pass from one 

 part of it to another as well as profoundly to investigate any one point. 

 It is the same with all departments of knowledge. The superiority of 

 a man consists in his being able to grasp the whole of a subject, as 

 well as its details, and to turn rapidly to each. Thus will the able 

 lawyer descend from the high principles of justice to the articles of a 

 code and the minute details of a cause, and again rapidly rise to the 

 theory of law. A great General will turn from strategical questions to 

 the concerns of the commissariat, and from the scrutiny of an advanced 

 post to a diplomatic correspondence. And this universal (so to speak) 

 knowledge is eminently valuable to a writer who works both in de- 

 scription and classification, the latter requiring a full consideration of 

 all the organs, their situation and evolution, of the affinities of plants, 

 their properties, physiology, and geographical distribution ; and it also 

 demands an acquaintance with the principles of nomenclature, the im- 

 portance of characters, and the value of previous publications on the 

 subject. All these points must be borne in mind and weighed ; and 

 it is thus the various mental qualities are brought into action. 



For the above reasons, the work of classification is far more difficult 

 than it appears, and very few men perform it thoroughly well. But 

 on the other hand, such labours amply reward those who pursue them, 

 for nothing in science lasts so long. It is plain that books of physio- 

 logy become antiquated and useless, whenever chemistry changes, and 

 the transitions of that science are not few. Who cares for the micro- 

 scopical observations made in the time of Grew and Malpighi ? Nor 

 are those in the beginning of the century much more consulted, except 

 for the purpose of following the history of the study. Opticians and 



