4 MANUAL OF HISTOLOGY. 



tion. By him the cell was proved to be the starting-point of all animal 

 structures. He also indicated the mode of origin of the various tissues 

 from the cell. It may be said that many points in relation to this fact 

 were known before Sclnuanris time, and that he came to false conclusions 

 in many things : but though this be true, the merit, nevertheless, remains 

 with him of having been the first to make prominent this fundamental 

 principle the greatest discovery of histology by an overwhelming mul- 

 titude of facts in detail. Schwann may therefore be hailed as the founder 

 of the science of " HISTOGENESIS," or the study of the origin of tissues one 

 of the most important subjects which can come under our consideration, 

 and one which has more recently undergone very extensive elaboration at 

 the hands of Reicliert, Koelliker, Remak, and others. 



Another branch of histology, again, has gradually become distinct from 

 the study of the nature of the textures in the normal state. This, which 

 deeply aifects pathology, is the consideration of the modifications which 

 tissues undergo in diseased conditions. J. Miiller may be looked upon 

 as the originator of this particular line of study, known as " PATHO- 

 LOGICAL HISTOLOGY," while more recently Virchow has become famous 

 for his great efforts in the same direction. To these two may be added 

 the well-known names of some of the disciples of the latter, as, for in- 

 stance, those of Recklingliausen, Rindfleisch, and Colmheim. 



Like pathological, so is also "COMPARATIVE HISTOLOGY " indispensable for 

 a scientific knowledge of the finer structure of the animal frame ; and yet, 

 in spite of numerous individual efforts, and the most ingenious researches, 

 this branch is still in its infancy, owing to the immense amount of matter 

 to be dealt with. To this particular field of investigation Mutter, Siebold, 

 Koelttker,Leydig,,a.i\d. others, have devoted their great talents with the 

 happiest results. 



REMARKS. The microscope, its construction, way to work with it, &c., has become 

 lately the theme of many literary effusions. We will only mention here one of the 

 more important essaj's on the subject C. Robin, Du Microscope et des injections, 2d 

 fd., Paris, 1871. Queckctt, "A Practical Treatise on the Use of the Microscope," 

 Loncl., 1848. W. Carpenter, "The Microscope," 3d ed., London, 1862. //. 

 Schacht, "Das Mikroscop," 3 Auf., Berlin, 1862. L. Beetle, " How to work with 

 the Microscope," 4th ed. ; and "The Microscope in Medicine," just published. 

 //. Frey, " Das Mikroskop und die mikroskopische Technik," American Transl.- - (2.) 

 Schwann's works are to be found in an attractive little book, "Mikroskopische 

 Untcrsuchungen liber die Ueberemstimnmng in der Struktur und dem Wachstum 

 tier Thiere und Pflanzen," Berlin, 1839. (3.) As to the rich literature of Histology, 

 which is in its origin chiefly German (as this whole branch of anatomy is essentially 

 the production of German industry), we shall only mention a few handbooks and 

 other similar aids, and even these only sparingly. Among the older works which 

 deserve mention are, A. Koelliker, "Handbuch der Gewebelehre des Menschen," 

 Leipzig, 1852. 5 Auf., 1857; and besides German works, Todd and Bowman, 

 "Anatomy and Physiology of Man," Lond., 1856. 2 vols. L. Bcale, "The 

 Structure of the Simple Tissues," Last ed. A. Eckcr's copper -plates in Wagner 's 

 Icones pliijswlogicce., may also be recommended. 



4- 



In an' earlier section we have seen that the study of the anatomical 

 characters of tissues is the offspring of a comparatively late era of natural and 

 medical science. But the chemistry of the -tissues, or " HISTOCHEMISTRY," 

 is of more recent origin still. And in that an acquaintance with the com- 

 position of the different structures of the body can only be gained by the 

 application to them of the facts of organic chemistry, so is histochemistry 



