126 BIOLOGY AND ITS MAKERS 
Aristotle, who attempted, and in part indeed successfully, to 
set up a larger number of groups. 
‘But in his successors even more than in Linnzus himself 
we see the damage wrought by the purely systematic method 
of consideration. The diagnoses of Linnzus were for the 
most part models, which, mudatis mutandis, could be employed 
for new species with little trouble. There was needed only 
some exchanging of adjectives to express the differences. 
With the hundreds of thousands of different species of 
animals, there was no lack of material, and so the arena was 
opened for that spiritless zodlogy of species-making, which 
in the first half of the nineteenth century brought zodlogy 
into such discredit. Zodlogy would have been in danger of 
growing into a Tower of Babel of species-description if a 
counterpoise had not been created in the strengthening of the 
physiologico-anatomical method of consideration.” 
His Especial Service.—Nevertheless, the work of Lin- 
neus made a lasting impression upon natural history,and we 
shall do well to get clearly in mind the nature of his particular 
service. In the first place, he brought into use the method 
of naming animals and plants which is employed to-day. In 
his Systema Nature and in other publications he employed 
a means of naming every natural production in two words, 
and it is therefore called the binomial nomenclature. An 
illustration will make this clearer. ‘Those animals which had 
close resemblance, like the lion, tiger, leopard, the lynx, and 
the cat, he united under the common generic name of Felis, 
and gave to each a particular trivial name, or specific name. 
Thus the name of the lion became felis leo, of the tiger Felis 
tigris, of the leopard Felis pardus, of the cat Felis catus ; and 
to these the modern zodlogists have added, making the 
Canada lynx Felis Canadensis, the domestic cat Felis domes- 
tata, etc. In a similar way, the dog-like animals were 
united into a genus designated Canis, and the particular 
