JvxE", 1895.] 



SCIENCE. 



631 



seventy-eight, after a life rich iu scientific 

 achievement. 



The world at large can never realize the 

 gi'eat debt that the world of science, and 

 through it the world at large, owes to the 

 tireless brain and the skilful hand of this 

 modest Leipsic professor. Ludwig com- 

 bined, in an almo.st ideal manner and insep- 

 aral)ly, great investigating power and gi-eat 

 teaching power. An investigator himself, 

 throughout the course of his busy life he 

 ti-ained between two and three hundred in- 

 vestigators, and more than anj- other man 

 since Johannes Miiller he has directed the 

 coui-se of physiological research. The num- 

 berless publications from his laboratory 

 bear the names of his iiupils and rarely his 

 own, but the inscription, ' Aus dem physio- 

 logischen Institut zu Leipsic,' is the seal of 

 their worth. 



Ludwig was a man of the broadest sym- 

 pathies and culture, restless and eager for 

 knowledge within or without the bound- 

 aries of his own science. But he was con- 

 tent to study specific problems and to refi-aiu 

 from baseless and sweeping hypotheses. In 

 the fiftj'-three years of his constant labor 

 he left untouched few fields of the phj'siol- 

 ogy of his time, and he never delved lightly 

 or superficiallj'. A record like his is rarely 

 equalled. To the end he maintained his 

 interest and activity ii-esh, and at the age of 

 seventy-five he wrote to an American 

 Mend, ■' Ueberall liegt so viel brach, iiberall 

 giebt es so viele Liicken, dass man bald 

 mehr Aufgaben als Kriifte besitzt."' 



It was a memoi'able day for biology when 

 Ludwig conceived the idea of the kymo- 

 graph, the instrument used for recording 

 physiological movements, for the invention 

 of the kymograjih marked the introduction 

 of the graphic method into physiology. 

 Ludwig once wi-ote, " Observ-ation and ex- 

 periment alone bring the light that illumin- 

 ates the secret ways of nature.'' The graphic 

 method has made observation and experi- 



ment exact, and has revolutionized the bio- 

 logical sciences. Ludwig is responsible 

 for much of the apparatus of precision now 

 in use in physiological laboratories. To 

 him must be ascribed also the fruitful 

 method of separating single organs from the 

 rest of an animal body, and maintaining 

 them for study in a vital condition, a pro- 

 cess indispensable to the understanding of 

 function iu a complicated organism. 



Besides these additions to method, among 

 the more noteworthy of his many contribu- 

 tions to physiology, either alone or in con- 

 junction with his pupils, may be mentioned: 

 numerous facts and principles regarding the 

 dynamics of the circulation of the blood ; 

 the details of the hearfs action ; the loca- 

 tion of the vaso-motor centre ; the discovery 

 of the depressor nerve ; the mutual relations 

 of respiration and circulation ; the blood 

 gases ; many anatomical and physiological 

 advances regarding the Ij-mphatic system ; 

 the secretory function of the chorda tym- 

 pani nerve ; the mutual relations of gland 

 secretion and blood circulation; gas exchange 

 and production of heat in tissues ; the pres- 

 ence of inosit, uric acid and other substan- 

 ces in the animal body ; numerous facts 

 regarding the metabolism of specific tissues; 

 the cour.se taken bj' the food-stufls in ab- 

 sorption ; the minute physiological anatomy 

 of the kidney, the liver, the intestine, the 

 pancreas, the salivary glands, the heart, the 

 skin, etc.; manj- facts regarding general 

 muscle and nerve physiologj', the central 

 nervous system and the special senses. 



The leading events in Ludwig's life are 

 as follows : Carl Friedrich Wilhelm Lud- 

 wig, the son of a Hessian army officer who 

 served in the Napoleonic wars, born in Wit- 

 zeuhausen December 29th, 1810; studied in 

 Erlangen and Marburg: M. D., Marburg, 

 1839 ; prosector in anatomy, Marburg, 1841 ; 

 privat-docent in physiology, Marburg, 1842; 

 extraordinary professor of comparative anat- 

 omy, Marburg, 184(); professor of anatomy 



