THE GENERAL CONSTITUTION OF LIVING BEINGS. 67 
to sight some of the cells, pores, and excessively small 
tubes, which thus group together to form the solid parts 
observable by the naked eye. Gruthuisen, Heusinger, 
Schleiden, Schwann, and others, thus unfolded the system 
of general anatomy expounded by Xavier Bichat. 
Medicine of old had believed in the strangest doctrines 
as to the liquids of the system, and had connected them in 
the wildest ways with its theories upon health and disease. 
The Hippocratists and Galen, at a later time, supposed 
there were four humors, the blood, the phlegm, yellow bile, 
and black bile, whose due attempering supported health, 
while their disproportion or acridity occasioned diseases. 
Moderns were for a long time satisfied with these delusive 
views, and it was not until the eighteenth century that a 
true advance was made in the knowledge of the humors, 
thanks to the labors of the younger Rouelle. After him, 
Fourcroy, Vauquelin, Berzelius, Chevreul, Liebig, Dumas, 
Denis, etc., using the exact method of chemical investiga- 
tions in the study of these interesting parts, grew ac- 
quainted with the chemical compounds, the immediate 
principles out of which they are formed. They also tried 
to detect and measure these principles in the organs and 
tissues of the system. Unfortunately, chemistry does not 
avail to solve all the problems of biology, and in our day 
we have acknowledged that chemical analysis must give 
precedence to anatomical analysis in researches into the 
composition of the machinery of the organism. In this 
way there came to be formed a more complete general anat- 
omy than that of Bichat, one that embraced the study 
by method of animated beings, beginning with their most 
rudimentary component principles, and ending with those 
complex tissues which are the web of their organs. 
Il. 
Every one knows how geologists decompose systems 
Into rocks, and rocks into minerals, which are the primary 
