Sir John Lubbock’s Address. 275 
which led to the dentonatration of the general law of develop- 
ment for all organic elementary tissues. 
As regards descriptive biology, by far the greater number of 
species now recorded have been named and described within 
the last half-century, and it is not too much to say that not a 
day passes without adding new species to our lists. A compari 
son, for instance, of the edition of Cuvier’s “ Regne Acuna ie 
published in 1828, as compared with the" present state of our 
knowledge, is most strikin 
Dr. Giinther has been good enough to make a calculation for 
me. e numbers, of course, are only approximate, but it 
appears that while the total number of animals described a 
to 1831 was not more than 70,000, the number now is at leas 
320,000. 
Lastly, to rei how large a field still remains for a 
I may add that Mr. Waterhouse estimates that the 
Museum trea phot: not fewer than 12,000 species of 1 a 
which have not yet been described, while our collections do not 
probably contain anything like one-half of those actually in 
existence. Further than this, the anatomy and habits even of 
those which have been described offer an inexhaustible field for 
research, and it is not going too far to say that there is not a 
eee species which would not amply repay the devotion of a 
i 
One remarkable feature in the modern progress of biological 
science has been the application of improved methods of obser 
vation and experiment; and the employment in physiological 
research of the exact measurements employed the experi- 
mental physicist. Our microscopes have been greatly improved : 
achromatic object-glasses were introduced by Lister in 1829; 
the binocular arrangement by Wenham in 1856; while immer- 
sion lenses, first suggested by Amici, and since carried out 
under the formula of Abbe, are most valuable. The use of 
chemical reagents in microscopical investigations has proved 
most instructive, and pieiep very important m method of inves- 
Separate sections of the egg of a beetle, or the brain of a bee. 
At the close of the last century, Sprengel published a most 
Suggestive work on flowers, in which he pointed out the curious 
relation existing between these and insects, and showe aig 
the latter carried the pollen from flower to flower. His o 
vations, however, attracted little notice, until Darwin called 
attention to the subject i in 1862. It had long been known that 
the cowslip and primrose exist under two forms, about e ually 
numerous, and differing from one another in the arrangements 
