114 THE HISTORY OF BIOLOGY 



as in the work Classes plantarum, published in Holland in 1738, he promul- 

 gated what he called "fragments of a natural method of arrangement": a 

 list of sixty-five "orders," each embracing a number of vegetable genera, 

 but without any characterization of the peculiarities that warranted their 

 being grouped together. By way of introduction he describes the natural 

 system as the highest, but hitherto unattained, aim of botany, which he 

 exhorts all truly distinguished botanists to strive after. For the creation 

 of such a system no particular parts of plants or flowers should, he maintains, 

 be used as a standard, but only the common agreement existing between all 

 parts of the plant. Several of the groups which he founded, such as palms, 

 grasses, Liliaceas, Umbellata, are still regarded as entirely natural. Through- 

 out the whole of the rest of his life Linnasus never let the natural system out 

 of sight, although he never thought that he would complete it. In his Philo- 

 sophia botanica(i-j'^i)hc again cites a number of natural groups, now provided 

 with names, and in doing so points out that the vegetable groups everywhere 

 border on one another, like the countries on a map of the world. In point of 

 fact, his realization of the difficulty of trying in a comprehensible way to 

 present the natural affinities of living creatures was a proof of his keen eye 

 for the infinite multiplicity of nature; his caution might well be borne in 

 mind by many a biologist of our own time who has rashly drawn up a genea- 

 logical tree for some animal group or other. In connexion with this feeling 

 of Linnxus for the difficulty of determining natural affinity, it is worth 

 mentioning that in his later writings he discusses with far greater caution 

 than in his earlier years the question of the bordering of the species on one 

 another. It was not only that he had seen masses of varieties overlapping one 

 another, but he had also observed the altered forms produced by hybridiz- 

 ing — he himself was very successful in hybridizing in his own garden — 

 and as a result of all this the delimitations of species, which he once felt to 

 be so certain, began to be obliterated. The doctrine of the original creation 

 he certainly could not abandon, but he began to consider the possibility of 

 the genera's having been created and only one or a few species of each, and 

 afterwards new species' being able to arise out of the old. In the final edition 

 of Systema natura he has omitted the definite assertion that no new species 

 arise. He who has so often been accused of dogmatism was really less dog- 

 matic than many modern scientists who have proved themselves ready to 

 accept blindly the prevailing theories of the day. 



In the above-mentioned Philosophia botanica Linnasus has also expounded 

 an organic theory in respect of the vegetable kingdom. A great many of his 

 clearly formulated characters of the various parts of plants are still valid to- 

 day. Many consider the anatomical section of this work to be weak, even as 

 compared with the investigations of the earlier botanical anatomists Mal- 

 pighi and Grew. This may be true, for Linnasus was, generally speaking, no 



