452 TROPICAL NATURE 



anatomy could be applied to the classification of animals 

 according to their whole organisation in a far more natural 

 manner than by the easier method of Linnaeus. Later on, 

 when improved microscopes and refined optical and chemical 

 tests became available, the study of anatomy was carried 

 beyond the knowledge of the parts and organs of the body 

 such as bones, muscles, blood-vessels, and nerves to the 

 investigation of the tissues, fibres, and cells of which these 

 are composed ; while the physiologists devoted themselves to 

 an inquiry into the mode of action of this complex machinery, 

 so as to discover the use of every part, the nature of its 

 functions in health and disease, and, as far as possible, the 

 nature of the forces which kept them all in action. 



Down to the middle of the present century the study of 

 nature advanced with giant strides along these separate lines 

 of research, while the vastness and complexity of the subject 

 led to a constantly increasing specialisation and division of 

 labour among naturalists, the result being that each group of 

 inquirers came to look upon his own department as more or 

 less independent of all the others, each seemed to think that 

 any addition to his body of facts was an end in itself, and that 

 any bearing these facts might have on other branches of the 

 study or on the various speculations as to the "system of 

 nature " or the " true method of classification " that had at 

 various times been put forth was an altogether subordinate 

 and unimportant matter. And, in fact, they could hardly 

 think otherwise. For, while there was much talk of the 

 "unity of nature," a dogma pervaded the whole scientific 

 world which rendered hopeless any attempt to discover this 

 supposed unity amid the endless diversity of organic forms 

 and structures, while so much of it as might be detected 

 would necessarily be speculative and unfruitful. This dogma 

 was that of the original diversity and permanent stability of 

 species, a dogma which the rising generation of naturalists 

 must find it hard to believe was actually held, almost 

 universally, by the great men they look up to as masters in 

 their several departments, and held for the most part with 

 an unreasoning tenacity and scornful arrogance more suited 

 to politicians or theologians than to men of science. Although 

 the doctrine of the special and independent creation of every 



