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. 



II. 



Every one knows how geologists decompose systems 

 into rocks, and rocks into minerals, which are the primary 



