Histology

“ The number of living investigators in histology is enormous; and their work in the subject of cell-structure and in the department of embryology now overlaps.
In pathological histology may be observed an illustration of the application of biological studies to medicine. While no attempt is made to give an account of these practical applications, they are of too great importance to go unmentioned. Histological methods are in constant use in clinical diagnosis, as in blood counts, the study of inflammations, of the action of phagocytes, and of all manner of abnormal growths. ”

“ Only a small part of morphology, which we botanists call anatomy, but which is identical with the histology of the zoologists, developed along with physiology. The greater part of morphology, which corresponds to what zoologists call anatomy, pursued its way independently of physiology. ”

“ The great merit of the nineteenth century, as far as our knowledge of the human frame is concerned, lies in the founding of two new lines of research of immense importance—comparative anatomy and histology, or microscopic anatomy. ”

“ These men in particular may be remembered as the investigators who expanded the work of Bichat on the tissues: Schwann, for disclosing the microscopic elements of animal tissues and founding the cell-theory; Koelliker, as the typical histologist after the analysis of tissues into their elementary parts; Virchow, as extending the cell-idea to abnormal histology; Leydig, for applying histology to the lower animals; and Ramon y Cajal, for investigations into the histology of the nervous system. ”

“ Histog′eny, the formation and development of tissues—also Histogen′esis; Histog′raphy, a description of the tissues.—adjs. Histolog′ic, -al, pertaining to histology.—ns. Histol′ogist, one skilled in histology; Histol′ogy, the science which classifies and describes the structural or morphological elements which exist in the solids and fluids of organised bodies; Histol′ysis, degeneration and decay of organic tissue.—adj. ”

“ Histology is another proxy for growth, and could be incorporated into this type of analysis to test its consistency with other growth characters. If histological data prove more reliable than other growth proxies, it should provide more resolved and robust trees that can be used to identify other sources of variability. ”

“ But there are not as many different types of histological structure as there are typically placed organs: on the contrary there are many elementary organs of the same type in different typical parts of the organism, as all of you know to be the case with nerves and muscles. It will not be without importance for our future theory of development, carefully to notice this fact, that specialisation in the position of embryonic parts is more strict than in their histology. ”

“ All these parts constitute microscopic anatomy or 'Histology.' These parts are constantly being changed; every part is constantly growing, decaying, and being replaced during the life of the animal. The tissue is constantly replaced by new material ”

“ One or two other facts deserve mention, as showing the readiness of our medical community to receive and adopt any important idea or discovery. The new science of Histology, as it is now called, was first brought fully before the profession of this country by the translation of Bichat's great work, “Anatomie Generale,” by the late Dr. ”

“ The work combines an abundance of well-chosen and most accurate illustrations, with a concise text, and in such a manner as to make it both atlas and text-book. The great majority of the illustrations were made from sections prepared from human tissues, and always from fresh and in every respect normal specimens. The colored lithographic plates have been produced with the aid of over thirty colors. ”

“ Thanks to the intimate alliance of morphology with medicine, the natural history of disease has, at the present day, attained a high degree of perfection. Accurate regional anatomy has rendered practicable the exploration of the most hidden parts of the organism, and the determination, during life, of morbid changes in them; anatomical and histological post-mortem investigations have supplied physicians with a clear basis upon which to rest the classification, of diseases, and with unerring tests of the accuracy or inaccuracy of their diagnoses. ”

“ In the department of anatomy and development, a host of accurate and patient inquirers, aided by novel methods of preparation, which enable the anatomist to exhaust the details of visible structure and to reproduce them with geometrical precision, have investigated every important group of living animals and plants, no less than the fossil relics of former faunæ and floræ. An enormous addition has thus been made to our knowledge, especially of the lower forms of life, and it may be said that morphology, however inexhaustible in detail, is complete in its broad features. ”

“ We possess no pedigree or armorial bearings; and we have to discover and trace the many diverging lines of descent in our natural genealogies, by characters of any kind which have long been inherited. Rudimentary [1] organs will speak infallibly with respect to the nature of long-lost structures. Species and groups of species which are called aberrant, and which may fancifully be called living fossils, will aid us in forming a picture of the ancient forms of life. Embryology [Pg 30] will often reveal to us the structure, in some degree obscured, of the prototypes of each great class. ”

“ Colour, hair, skin, bone, stature—all [24] these are points of physical conformation or structure; material and anatomical; points which the callipers or the scalpel investigates. But colour, hair, skin, bone, and stature, are not the only characteristics of man; nor yet the only points wherein the members of his species differ from each other. There is the function as well as the organ; and the parts of our body must be considered in regard to what they do as well as with reference to what they are. ”

“ By Othniel Charles Marsh, Professor of Paleontology in Yale College, New Haven, Conn.
Fossil anatomy is generally regarded as one of the driest of subjects; but, when the vestiges of old bones become the keys to the history of the world and the mysteries of the universe, their study acquires an intense interest. ”

“ On the other hand, there are anatomists and histologists who think it possible to obtain a true knowledge of animal and vegetable bodies merely by a most careful examination of the inner structure of the body of some individual species, without the comparative examination of the bodily form of all kindred organisms. And yet here, as everywhere, the internal and external factors, to wit, Inheritance and Adaptation, stand in the closest mutual relation, and the individual can never be thoroughly understood without a comparison of it with the whole of which it is a part. ”

“ The gradation, too, from the organisms whose types are said to be lost or destroyed, and confused in innumerable heaps, up to the perfect and complete specimen, is no fanciful representation of the resurrection; while the isolated bones and parts of skeletons which, though found far apart, as they were created, have been fitted together by the skill of the accomplished anatomist, give assurance of the fact that our scattered dust—our membra disjecta—shall come together at the sound of the last trump. ”

“ We watch the different tools and the traces of the way things16 were done—how the burials were arranged, what the living-places were like, and so on. We wonder about the people themselves, for the traces of habits and traditions are useful to us only as clues to the men who once had them. So we ask the physical anthropologists about the skeletons that we found in the burials. The physical anthropologists tell us about the anatomy and the similarities and differences which the skeletons show when compared with other skeletons. ”

“ It is equally true that palaeontological evidence has frequently failed where we most sorely needed it. The student must therefore resort to what may be called a tripod of evidence, derived from the available facts of embryology, comparative anatomy and palaeontology. ”

“ Importance of the Study of Morphology.—The study of morphology is of high importance in biology, and even more so in anthropology. And since the organism is a harmonic whole, in which the parts and their functions are closely interrelated, any external anomaly leads us to assume that there are corresponding anomalies of the internal organs, and hence, functional anomalies; hence also, in man, psychic anomalies. ”

“ When it is a question of giving or imagining an explanation of vital facts, of heredity, etc., biologists unable to supply anything beyond the details of structure revealed by anatomy have had recourse to hypothetical elements, gemmules, pangenes, biophores, and different kinds of determinants. ”

“ The Museum, he said, had "only a beginning of such an anatomical collection as I have indicated is desirable * * *. We are accustomed to think that human anatomy is exhausted as a field for original research," a view to which the speaker did not subscribe. "There is ample material and scope for original work for half a dozen skilled anatomists for many years to come to supply the demands of this museum for illustrations of human morphology * * *," he added. ”

“ One of his favourite arguments—and it is a weighty one, though neglected by the orthodox Darwinians—is that living substance is capable, under similar stimuli, of developing spontaneously and afresh, at quite different points and in different groups, similar organs, such as spots sensitive to light, accumulations of pigment, eye-spots, lenses, complete eyes, and similarly with the notochord, the excretory organs, and the like. Therefore homology of organs is no proof of their hereditary affiliation.28 They rather illustrate “iterative evolution.” ”

“ The results of Comparative Anatomy enable us to decide with more or less confidence as to the degrees of relationship between the groups of organisms, and to distinguish between the more primitive and the more specialized; the study of Embryology is, at least, an indispensable adjunct to Comparative Anatomy, even if it does not, as was once supposed, give us an actual recapitulation of ancestral history ”

“ The solution of some of the most difficult problems in anatomy has received scarcely less aid from the extinct forms discovered than from embryology; and the two lines of research supplement each other. Our present knowledge of the vertebrate skull, the limb-arches, and the limbs, has been much enlarged by researches in paleontology. ”

“ In a series of display cases projecting from the walls, the Museum displayed anatomical and pathological specimens so arranged as to tell, for each organ and region of the body and for the human organism as a whole, the story of normal development, abnormal deviations, disorders and diseases, and repairs and restoration, including that by surgery. ”

“ Embryology and Ontogeny.—In following the discovery of the law of recapitulation among palaeontologists we have clearly stated the chief contribution of palaeontology to the science of ontogeny—namely, the correspondences and differences between the individual order of development and the ancestral order of evolution. ”

“ It is thus clear that a high value attaches to these specimens if they be regarded as documents testifying to the course of human evolution. When the bones are examined, the contrast they provide with all human remains is so marked as to emphasise at once the necessity for a thorough and critical examination of their structure. ”

“ If now, instead of seeking for evidences of man's ancestry within the human body, in survivals of ancient anatomical structures, we seek for them within the crust of the earth, we find ourselves confronted with evidences of a great antiquity of the human race, partly in implements of human manufacture, partly in ancient or fossilized bones of primitive man. ”

“ Had those ancient physicians, who often prescribed these roots, and paid attention to the colour of the excrements of their patients, been accustomed to open their bodies when they died under their hands, they would have perhaps remarked, in human bones, what was observed long after in the bones of animals, when the roots were no longer used in medicine ”

“ How, then, comes it, may the reflective mind repeat, that the grand Tissue of all Tissues, the only real Tissue, should have been quite overlooked by Science,—the vestural Tissue, namely, of woollen or other cloth; which Man's Soul wears as its outmost wrappage and overall; wherein his whole other Tissues are included and screened, his whole Faculties work, his whole Self lives, moves, and has its being? ”

“ Moreover, in addition to the direct advance in the method and scope of anatomical teaching afforded by these aids, it is further hoped that the broader interpretation, both of structure and function, obtained by ontogenetic and phylogenetic comparison, will impart an interest to the study of adult human morphology, such as the subject, considered solely in the narrow field of its own limitations, could never arouse. ”

“ Our museums exhibit fossil shells of immeasurable antiquity, as perfect as the day they were formed, whole skeletons without a limb disturbed—nay, the changed flesh, the developing embryos, and even the very footsteps of primeval organisms. ”

“ In the next place, Physical Anthropology, not only in respect to [37] human palaeontology, but in general, is as barren of explanations as it is fertile in detailed observations. The systematic study of heredity as it bears on the history of the human organism has hardly begun. ”