472 GROWTH OF BIOLOGY IN THE NINKTEENTH CENTURY. 



the like was aeconiplishi^d in many other cases, until now the auda- 

 cious hope can be cherished that some da}^ chemistry may peihaps 

 even pei-form the synthesis of albumen, the most complex of all 

 organic substances. Chemistry has, however, progi-essed f urthei" in the 

 analysis than in the synthesis of these organic l)odies from whi('h the 

 cells, tissues, and juices of plants and animals are built, having ana- 

 lytically investigated the carbohydrates, fats, alVjuminous bodies, and 

 their numberless derivatives and products of decomposition. Thus 

 has a i)liysi()l()gical chemistry gradually been developed — a science rich 

 in results, from which still more weighty disclosures are awaited in the 

 future. 



The chemical processes upon th(^ normal course of which life depends 

 were iiatui-ally in great measure opened up to us l)v the increased 

 knowledge of organic su))stan<'es. PHiiger's invention of the mercu- 

 rial gas pump and other important apparatus and the improvement of 

 chemico-physiological methods generally imparted a powerful upward 

 impulse to the physiology of respiration, of the formation of l)lood, 

 of assimilation and secretion: while extensive and laborious experi- 

 mental investigations l)y Claude Bernard, Pettenkofer and Voit, Lud- 

 wig, PHiiger. IleidcMihain, and many others successfully elucidatinl the 

 digestion of all)uniinous bodies, fats, and carl)ohydrates and the func- 

 tions performed ])y the salivary glands, stomach, ii\-er, and panci-eas. 



Sinndtaneoiisly with trium])hantly raising its head in the chemical 

 direction, physiologv did tlu' same thing in the physical direction. In 

 its contest with vitalism, which held to the assumption of special vital 

 forces as needed for the explanation of life, thus erecting a rigid party 

 wall between the inorganic world and the empire of life, the highest 

 principle of physiology came to be that organisms are subject to the 

 universal laws of nature. Its guiding star was the law of the con- 

 servation of force, which was established by Robert Ma3'er and Helm- 

 holtz; while the highest goal of its research was the introduction of 

 physico-mathematical methods into physiology, by which it should 

 become possible, by the methods of weighing, measuring, and count- 

 ing, to penetrate the essence of the vital process and to render exact 

 account of the diiierent modes of energy which are distinguished as 

 mechanical, chemical, thermic, and electric. 



Then broke the dawn of that glorious day when ph^'siolog}" was 

 enriched by apparatus of the most varied description and instruments 

 invented with great ingenuity. B3' means of the cymograph and the 

 myograph it succeeded in exhibiting to the eye upon the smoked plate 

 and in measuring with the greatest exactitude the minutest features of 

 motions of living organs, of the wall of the heart and those of the 

 blood vessels, as well as the motions of the muscles. Galvanometer, 

 rheostat, and slide-induction apparatus, tangent galvanometer, became 

 common in the armamentarium of every physiological institute in 

 order that the electrical phenomena of muscular action and the 



