TRANSACTIONS OF THE SECTIONS. 119 



Anatomy and Phtsiologt. 



Address to the Department of Anatomy and Physiology. 

 By Professor EuTiusEyoRD, F.R.S.E. 



In addressing you upon the subjects of anatomy and physiology, I Avould invite 

 your attention to some of the features which characterize these departments of 

 biology at this present time, and to some recent advances in physiology, the con- 

 sideration of which you will find to be possessed of deep interest and importance. 



State of Anatomy. 



Anatomy, dealing as it does merely with the structure of living things, is a far 

 simpler subject than physiology, whose province it is to ascertain and explain their 

 actions. It was not a difficult thing to handle such instruments as a knife and 

 forceps, and with their aid to ascertain the coarser structure of the body. Accord- 

 ingly, the naked-eye anatomy of man has been fully investigated ; and although the 

 same cannot be said of that of many of the lower animals, it is nevertheless, as far 

 as this kind of inquiry is concerned, a mere question of time as regards its comple- 

 tion. But minute or microscopic anatomy is in a different position. Requiring, as 

 it does, the microscope for its pursuit, it could not make satisfactory progress until 

 this insti'ument had been brought to some degree of perfection. Doubtless much 

 advantage is still to be derived from improvements in the construction of this 

 instrument ; but probably most of the future advances in our knowledge of the 

 structure of the tissues and organs of the body may be expected to result from the 

 application of new methods of preparing the tissues for examination with such 

 microscopes as we now have at our disposal. This expectation naturally arises from 

 what has been accomplished in this direction during the last fifteen years. For 

 example, what valuable information has been gained regarding the structure of 

 such soft tissues as the brain and spinal cord by hardening them with such an agent 

 as chromic acid, in order that these tissues may be cut into thin slices for micro- 

 scopical study. How greatly has the employment of such pigments as carmine, 

 aniline, and logwood facilitated the microscopical recognition of certain elements of 

 the tissues. What a deal we have learned regarding the structure of the capil- 

 laries and the origin of lymphatics by the eil'ect which nitrate of silver has of 

 rendering distinctly visible the outlines of epithelial cells. What signal service 

 chloride of gold has rendered in tracing the distribution of nerves by the property 

 which it possesses of staining nerve-fibrils, and thereby greatly facilitating their 

 recognition amidst the textures. Moreover of what value osmic acid has been in 

 enabling us to study the structure of the retina. In the hands of Lockhart Clarke, 

 Eecklinghausen, Cohnheim, Schultze, and others, these agents have furnished us 

 with information of infinite value ; and those who would advance microscopical 

 anatomy may do so most rapidly by working in the directions indicated by these 

 investigators. In human microscopical anatomy, indeed, there only remain for 

 investigation things which are profoundly difficult — such as, for example, the struc- 

 ture of the brain, the peripheral terminations of nerves, the development of nerve- 

 tissue, and other subjects equally recondite. But in the field of comparative 

 anatomy there is far greater scope for the histological investigator. He has only 

 to avail himself of those reagents and methods which have recently proved so useful 

 in the microscopical anatomy of the vertebrates ; he has only to apply those more 

 fully than has yet been done to the invertebrates, and he will scarcely fail to make 

 discoveries. For the lover of microscopical research there is, moreover, a wide field 

 of inquiry in the study of comparative crabiyology — that is to say, in the study of 

 the development of the lower animals. Since it has become clear that a Iniowledge 

 of the precise relations of living things one to another can only be ai'rived at by 

 watching the changes through which they pass in the course of "their development, 

 research has been vigorously turned in this direction ; and although an immense 

 mass of facts has long since been accumulated regarding this question, Parker's 

 brilliant researches on the development of the skull give an indication of the great 

 things which we may yet anticipate from this kind of research. Speaking of micro- 



