MEMBERS OF THE MICROSCOPIC SECTION. 305 
supposed fact can take its place amongst the indisputable 
records of scientific progress. 
But however difficult may be the observation of histo- 
logical facts, their interpretation is still more so. As the 
former inquiry regards the structure of objects, the latter 
has mainly reference to their functions. Now observers 
have rarely, if ever, the means of watching the objects 
they are studying in all the phases of their vital opera- 
tions ; hence, to a logical mind, much collateral informa- 
tion becemes essential to the comprehension of what is 
seen. It was here that Ehrenberg, the most justly dis- 
tinguished of microscopic investigators, so signally failed. 
He observed facts of structure accurately and well, but 
his mind was not adapted to their interpretation; hence 
the conclusions he arrived at, respecting the functions of 
organs, were rarely such as can now be accepted. 
The essential characteristic of a truly philosophical ob- 
server lies in his power of inducing from an aggregation 
of facts the relations which subsist between them. No 
fact either stands alone, or is the result of accident; and 
when these relationships are ascertained and expressed, in 
some brief but comprehensive formula, we obtain what is 
called a law. ‘To discover laws is the legitimate ambition 
of the highest intellects, as the undying distinction which 
such discoveries afford is one of its loftiest rewards; but 
so great is the labour and difficulty involved in the dis- 
covery of one such law, that it is only given to the loftiest 
intellects to wear the laurel-wreath. But let it be the 
ambition of each one of you to aim at the achievement of 
some such result. 
I am anxious that this address should not deal exclu- 
sively with general topics, but that it should assume a 
practical character, calculated to aid you in your future 
proceedings. The course that I should most strongly re- 
commend to any one just entering upon these pursuits, is 
