346 RECENT ADVANCES IN SCIENCE. 



In the physiology of respiration the view that the carbonic acid of 

 expired air was formed in the lungs by the oxidation of the carbon of 

 the blood, still found strenuous support; for Johannes Miiller found it 

 necessary to argue at great length that the researches of Magnus on 

 the gases of the blood had placed the matter in its true light. It had 

 been suggested that the red corpuscles were in some way also special 

 carriers of oxygen from the lungs to the tissues, but Miiller could not 

 regard tlris as anything more than a mere supposition. 



When it is borne in mind that injection with mercury was the one 

 method employed for tracing out the course of the lymphatics, it will 

 be readily understood how imperfect was the then knowledge of the 

 lymphatic system. And when it is also remembered that though 

 Dutrochet had long before used osmosis to help iu the interpretation of 

 the movements of liquids in living tissues, the exact researches of 

 Graham had yet to come, it will also be understood why, when questions 

 of absorptions and cognate questions of secretion came under consid- 

 eration, they were dealt with as questions in such a condition are dealt 

 even nowadays; much was said about them because little was known. 



Though Poisseuille, taking up the matter where it had been left by 

 Stephen Hales in the foregoing century, had begun, and the brothers 

 Weber were just continuing, the work of placing our knowledge of the 

 mechanics of the circulation on a sound and exact basis, and though 

 the then teaching of the mechanical working of the heart did not differ 

 widely from that of to-day, the gap which separates the then knowl- 

 edge of the circulation, even in its mechanical aspects, from that which 

 we possess to-day, is seen in all its width when I remind you that Carl 

 Ludwig's first paper was not published until Huxley had ceased to be 

 a student — until the year 1845. As to all that great part of the physi- 

 ology of the vascular system which concerns its government by the 

 nervous system, I will only say that in Miiller's great work may be read 

 the pages in which he deals with the conflicting opinions and indecisive 

 observations as to whether the brain and spinal cord have any influ- 

 ence over the heart-beat, and in which, marshaling with logical force 

 the arguments for and against the opinion that the blood vessels have 

 muscular fibers in their walls, finally decides that they have not. 



In the physiology of the nervous system a momentous advance had 

 been made some few years before, in the early thirties, by the introduc- 

 tion, through Marshall Hall, of the idea of reflex action. This was 

 rapidly supplying the key to many hitherto unsolved physiological and 

 clinical problems. The special functions of the several cranial nerves 

 were beiug worked out by Majendie, Reid, and others. The former 

 (with Flourens) was also making many experimental researches on 

 cerebral lesions; and, in another line of inquiry, Bidder and Volkmann 

 were preparing the way for discoveries to come by their important 

 studies on the sympathetic system. The jmysiology of the senses was 

 being vigorously pushed forward by Johannes Miiller; but the reader 



