Chap. XXII. CAUSES OF VARIABILITY. 251 



Those authors who believe that it is a law of nature that each 

 individual should differ in some slight degree from every other, 

 may maintain, apparently with truth, that this is the fact, not 

 only with all domesticated animals and cultivated plants, but 

 likewise with all organic beings in a state of nature. The Lap- 

 lander by long practice knows and gives a name to each 

 reindeer, though, as Linnaeus remarks, " to distinguish one from 

 another among such multitudes was beyond my comprehension, 

 for they were like ants on an ant-hill." In Germany shepherds 

 have won wagers by recognising each sheep in a flock of a 

 hundred, which they had never seen until the previous fortnight. 

 This power of discrimination, however, is as nothing compared 

 to that which some florists have acquired. Verlot mentions a 

 gardener who could distinguish 150 kinds of camellia, when not 

 in flower ; and it has been positively asserted that the famous 

 old Dutch florist Voorhelm, who kept above 1200 varieties of 

 the hyacinth, was hardly ever deceived in knowing each variety 

 by the bulb alone. Hence we must conclude that the bulbs of 

 the hyacinth and the branches and leaves of the camellia, though 

 appearing to an unpractised eye absolutely undistinguishable, 

 yet really differ. 1 



As Linngeus has compared the reindeer in number to ants, I 

 may add that each ant knows its fellow of the same community. 

 Several times I carried ants of the same species (Formica rufa) 

 from one ant-hill to another, inhabited apparently by tens of 

 thousands of ants ; but the strangers were instantly detected 

 and killed. I then put some ants taken from a very large nest 

 into a bottle strongly perfumed with assafcetida, and after an 

 interval of twenty-four hours returned them to their home ; 

 they were at first threatened by their fellows, but were soon 

 recognised and allowed to pass. Hence each ant certainly re- 

 cognises, independently of odour, its fellow ; and if all the ants 

 of the same community have not some countersign or watch- 

 word, they must present to each other's senses some distin- 

 tinguishable character. 



1 « Des Jacinthes,' &c, Amsterdam, lated by Sir J. E. Smith, vol. i. p. 314. 



1768, p. 43; Verlot, 'Des Varietes,' The statement in regard to German 



&c, p. 86. On the reindeer, see shepherds is given on the authority of 



Linnseus, « Tour in Lapland,' trans- Dr. Weinland. 



