dxxviii PROCEEDINGS—PERTHSHIRE SOCIETY OF NATURAL SCIENCE. 
in the direction of the Geographical Distribution of plants and 
Economic Botany. 
In 1838, the year after the Accession, a most important step in 
advance was made in structural Botany, for it was then that Schleiden, 
the great German Botanist, first pointed out that all vegetable tissues 
are built up on the cellular type, and that the plant embryo can 
always be traced back to a single nucleated cell. This discovery was 
the beginning of a long series of researches in the intimate structure 
of plant tissues. It was not until 1863, however, that the next 
important step was taken in the descending scale of analysis, namely 
the discovery, by Von Mohl, of Protoplasm, as the formative principle 
in the ovule and in the cells of all young plants. 
At the beginning of the Reign, namely in June, 1837, another 
most important discovery was made, for it was then that Cagniard 
Latour announced to the Academy of Sciences in Paris that Fermen¬ 
tation was produced by the multiplying of immense numbers of 
microscopic plants. The importance of this discovery and its bearing 
on many phases of modern life are enormous, for the Science of 
Bacteriology, which then sprang into existence, has almost revolu¬ 
tionised medical and surgical practice. In this connection it is suffi¬ 
cient merely to mention the names of Lister, Pasteur, and Koch, in 
order to remind you of the immense amount of human suffering and 
disease which have been prevented as the outcome of this discovery. 
In many other directions its effects have been nearly equally important, 
as for instance in Agriculture and in many of the industrial arts. 
Systematic Botany has made great strides since the beginning of 
the Reign, the most eminent workers in our country being Sir Joseph 
Hooker, Asa Gray, Bentham, Oliver, and Balfour. The results of 
these investigations are embodied in many most important systematic 
works, such as the “Genera Plantarum,” the “British Flora,” the 
“ Flora of India,” etc. 
(b) Zoology. —In this department of Biology, as in the last, the 
beginning of the reign marked a period of transition. Men were 
beginning to see that there were many facts in animal life and 
structure which they could not explain, and seemed to be feeling 
vaguely for the key to the problem. That key, however, was not 
found until more than a score of years later. In the early years of 
the century the chief zoological activity was centred in Paris, where 
three great naturalists were at work, each working in harmony with 
the others, but each on distinctive lines of his own. The first of 
these was Cuvier, whom we may almost call the founder of Com¬ 
parative Anatomy. It was he who first divided the animal kingdom 
into Vertebrate, Articulate, and Radiate animals, and who did so 
much to clothe the bones of extinct Vertebrates almost with flesh 
and blood. The second, Geoffroy St. Hilaire, was the first to 
demonstrate the Homology of animals, that is, the unity of plan in 
animal structure. The third of the group, Lamark, has been called 
the founder of “ Philosophical Zoology,” for he was one of the most 
eminent of those who speculated in evolutionary hypotheses before 
the time of Darwin. He saw clearly that animals of a similar type 
must have had a common origin, but he failed to see the way 
