186 BIOLOGY AND ITS MAKERS 
to make physiology broadly comparative. So comprehensive 
was his grasp upon the subject that he gained for himself 
the title of the greatest physiologist of modern times. He 
brought together in his great work on the physiology of man 
not only all that had been previously made known, carefully 
sifted and digested, but a great mass of new information, 
which was the result of his own investigations and of those 
of his students. So rigorous were his scientific standards 
that he did not admit into this treatise anything which had 
been untested either by himself or by some of his assistants 
or students. Verworn says of this monumental work, which 
appeared in 1833, under the title Handbuch der Physiologte 
des Menschen: ‘“‘This work stands to-day unsurpassed in 
the genuinely philosophical manner in which the material, 
swollen to vast proportions by innumerable special researches, 
was for the first time sifted and elaborated into a unitary 
picture of the mechanism within the living organism. In this 
respect the Handbuch is to-day not only unsurpassed, but 
unequalled.” 
Miiller was the most accurate of observers; indeed, he is 
the most conspicuous example in the nineteenth century of a 
man who accomplished a prodigious amount of work all of 
which was of the highest quality. In physiology he stood on 
broader lines than had ever been used before. He employed 
every means at his command—experimenting, the observa- 
tion of simple animals, the microscope, the discoveries in 
physics, in chemistry, and in psychology. 
He also introduced into physiology the principles of psy- 
chology, and it is from the period of Johannes Miiller that 
we are to associate recognition of the close connection be- 
tween the operations of the mind and the physiology of the 
brain that has come to occupy such a conspicuous position 
at the present time. 
Miiller died in 1858, having reached the age of fifty-seven, 
