( 266 ) 

 PEOGKESS OF MICEOSCOPICAL SCIENCE. 



Microscopic Anatomy : the Necessity of its Study. — In liis recent able 

 address to the department of Anatomy and Physiology at the Bradford 

 meeting of the British A ssociation, Dr. Eutherford made some impor- 

 tant observations and offered some sound advice to intending micro- 

 scopists. He considers that it is in a different position from ordinary^ 

 anatomy. Eequiring, as it does, the microscope for its pursuit, it 

 could not make satisfactory progress until this instrument had been 

 broiTght 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 know- 

 ledge 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 ex- 

 ample, what valuable information has been gained regarding the 

 structure of such soft tissues as the brain and spinal cord by harden- 

 ing them with such an agent as chromic acid, in order that these 

 tissues may be cut into thin slices for microscopical study. How 

 greatly has the employment of such pigments as carmine and the 

 aniline dyes fiicilitated the microscopical recognition of certain 

 elements of the tissues. What a deal we have learned regarding the 

 structure of the capillaries, and the origin of lymphatics, by the effect 

 which nitrate of silver has of rendering distinctly visible the outlines 

 of endothelial 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 recogni- 

 tion 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, Beale, Eecklinghausen, Cohnheim, Stultz, 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 investi- 

 gators. Tn human microscopical anatomy, indeed, there only remain 

 for investigation things which are profoundly difficult, such as, for ex- 

 ample, the structure 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 

 microscoincal 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 embryology ; that is to say, in the study of the develop- 

 ment of the lower animals. Since it has become clear that a know- 

 ledge of the precise relations of living things one to another can only 



