HISIXOERITE. 



HISTOLOQT. 



1M 









ink t tho point ; the culroen elevated ; 



. . ami. partty covered by membrane; logi hort; toe* 



, thre. in hoot, MM behind; cUwi curved ; wings long and 



// nrtiesj. UM Swallow. UM Chimney -Swallow. 



.oe, UM Martin, th* Martin-Swallow, the Hoiue-Martin. 



// rVawM. UM 8ad-Martin, UM Bank-Martin. 



CVfMtfc*. Back very abort, triangular at it* base, wide, concealed, 

 iliir i1.Ii| i si>*s>illC tiijnnil thi ijn upper mandible hooked 

 at UM point ; BMtrib longitudinal, near the ridge of the beak, open, 

 UM *agV* irniaod, and funuabed with atnall fcth.-n ; tani very abort ; 

 UM four, all directed forward* and entirely divided; claw* abort, 

 true*, and cunred ; wing* very long ; the first quill-feather a little 

 barter than the second. 



.IMC, the Swift, UM Swift Swallow, the Common Swift. 



C eV^u, UM Alpine Swift, the White-Bellied Swift 



For an account of the other member* of the family, *ce SWALLOW 

 TMML 



MISINCERITR [THBACUTE.] 



II 1STOLOGY (i<rri and A*TI), that department of science wbicb 

 embrace* the fact* relating to the ultimate structure of the part* of 

 plant* and animal*. Tbeee faeta have been usually comprehended 

 tinder UM term General Anatomy, but more recently it ha* been found 

 ootmnient to tu* the term Hutology. It i* only recently Out thi* 

 word could be needed, for the obeerration* upon which the science 

 i* founded hare only been made since the extensive employment of 

 the microscope. It may be said to have originated with Marcellus 

 Malpighi (im-M) and Anton Ton Leeuwenhoek (1622-1723) at the 

 time when magnifying glaase* were fint oonatruoted of auch a kind as 

 to be useful in observing the atrueture of plants and animal*. The 

 ultimate composition of organised bodie* wa* unknown to ancient 

 observers, a* well a* thoee who lived in the middle ages. It is true 

 that Aristotle and Oalen (peak of homogeneous and heterogeneou* 

 part* of the body ; and Kallopius, at the beginning of the 1 6th century, 

 nail pail itill more accurately the idea of what are now called the 

 tiaanrs of the body, yet the more minute structure of these part* was 

 entirely hidden from the*e observers. Even after the time of 

 Malpighi and Leeawenhoek HtUe was done towards unravelling the 

 intimate structure of the tiaiue* till the beginning of the present 

 eentnry. We can only point to such men as Fontana, Huys, 

 Ueberkuhn, Hewson, and Procbaska, a* having engaged in isolated 

 observation* upon the structure of various parts of the body. It was 

 not till the year 1801 that a connected view of the tissues of the 

 human body was given to the world, in such a form a* to lay the 

 foundations of what is now called the science of Histology. The 

 An.ton.ie Generate' (Paris, 1801) of Bichat was in fact the first 

 attempt to treat the - --y scientifically. It was not 



so much that Ittchat contributed new observations on tins subject, 

 a* that he systematically arranged what had hitherto been done, and 

 called attention to the importance of the subject, and to the fact 

 that it Uy at the foundation of all physiological and pathological 



In the d 







. . . 



In the direction of botany, the present century witnessed the obser- 

 vation* of Robert Drown, who wa* the first to draw the attention of 

 ******1trrlT to UM importance of niinuto observations on the tissues 

 One of the earliest attempt* at a systematic arrangement 

 of plant* wa* made by Slack, in the 39th volume 

 of UM ' TraasaoUoos of the Society of Arts,' in a paper on the 

 Elementary Tiasue* of Plant* and on Vegetable Circulation. Obser- 

 vation* upon the cellular and vascular structure of plant* multiplied, 

 and a freaUr value and interest wa* given to these than they had 

 before possMtd by the observations of S hleiden on the origin and 

 dv*lopaMatofUieeellsof|>lu]Uinbii|ia|- -r..n I'hytogenesis, published 

 i Mullet's ' Archiv fur Anatomic und Physiolngie,' Part iL, 183S. II, 

 her* printed oat, that in the formation of vegetable cell*, small 

 harpiyilennrd granule* are first generated in a gratuitous substance, 

 ami around them the cell-nuclei (cytoblasU) an found, which appear 

 like granolou* coagulations around the granule*. 



The remit* of these observation* were communicated in 1837 to 

 Uchwann, who, struck with the resemblance between the cells of 

 aahatl* and those of planta, conceived the idea that the same history 

 of devstopmssit wouldbefa 



I be found true of the parts of animals that had 

 be**) discovered by flchleiden In UM parts of plant*. From this time 

 UM scfeooK of HMotogy mad* rapid progrea*, and we cannot more 

 appropriately present its present condition than in the language of 

 ftufssjui KoUflMr, in hi* introduction to hi* ' Manual of Human 

 Hwtolo0:' 



In UM year 18M to (act the demonstration by Dr. Th. Schwann 

 of UM ./nginally perfectly identical cellular composition of all animal 

 orfuasCB*. and of UM origin of their higher structure* from these 

 sfasMwU, aflbrdfd UM appropriate conception which united all pre- 

 view iibaartatluus, and afforded a do* for further investigations. If 

 Btefcat fooadWd Histology more theoretically by constructing a system 

 *d carrying It out logically. Hchwann ha* by hi* investigation* 

 stated a baa* of fact*, and has thus won the second laurel* in this 

 Md. What ha* been done in this sciroce *inoc Bchwaun ha* l>een 

 Meed of grsat importance to physiology and medicine, and in fact 

 f great valtM in a purely sdenUflc point of view, inasmuch a* 



great deal which Schwann only indicated or shortly adverted to, as 

 the genesis of the cell, the import of the nucleus, the develops 

 the higher tisanes, their chemical relations, ftc., has received a further 

 development, but all this ha* not amounted to a step so greatly in 

 advance as to constitute a new epoch. If, without pretensions to 

 prescience, it be permitted to speak of the future, this condition of 

 Histology will hut a* long a* no essential advance is made towards 

 penetrating more deeply into organic structure, and becoming 

 acquainted with those elements of which that which we at present 

 hold to be simple is composed. If it be possible that the molecules 

 which constitute cell-membranes, muscular fibrils, axilo fibre of nerve*, 

 Ac., should be discovered, and the laws of their apposition and of the 

 alteration* which they undergo in the course of the origin, the growth 

 and the activity of the present so-called elementary parts, should be 

 made out, then a new era will commence for Histology, and the dis- 

 coverer of the law of cell-genesis, or of a molecular theory, will be as 

 much or more celebrated than the originator of the doctrine of the 

 composition of all animal tissues out of cells. 



" In characterising the present position of Histology aqd of it* 

 object*, we must by no means forget that, properly speaking, it con- 

 siders only one of the three aspects which the elementary parts p: 

 to observation, namely, their form. 



"Microscopical anatomy is concerned with the undent 

 of the microscopic forms, and with the laws of their structui 

 development, not with any general doctrine of the elementary 

 parts. 



" Composition and function are only involved so far as they relate 

 to the origin of forms and to their variety. 



" Whatever else respecting the activity of the perfect clement 

 their chemical relations is to be found in Histology, is tin-; 

 practical grounds, in order to give some useful triplication 

 morphological conditions, or to complete them, as, from it* ii 

 alliance with the subject, it is added only because physiology proper 

 does not afford a due place for the functions of the elem< 

 parts. 



" If Histology is to attain the rank of a science, its first need is to 

 have as broad and certain an objective basis as possible. To t i, 

 the minuter structural characters of animal organisms are to bo 

 examined on all sides, and not only in fully-formed structures, but in 

 all the earlier periods from their first development. 



" When the morphological elements have been perfectly made out, 

 the next object is to discover the laws according to which 

 uli'ivin one must not fail to have regard also to their relations of 

 composition ami function. In discovering these laws, here as in t he 

 exjieriniental sciences generally, continual observation MI 

 and more, among the collective mass of scattered facts iuul observe 

 tbe occasional from the constant, the accidental from the essential, till 

 at last a series of more and more rr'ieral < '\pr. . inn- 

 froin which in the end mathematical expressions or furnn 

 and thus the laws are enumerated. 



"If we inquire how fur Histology bos satisfied these requirements, 

 and what are iu prospects in the immediate future, the an.-u cr must 

 be a modest one. Not only does it not possess a single law, but the 

 materials at hand front which such nltould be deduced are | 

 relatively su scanty, that not v "isiderablu n nei.d 



prnp<jaitioii8 appear well founded. Not to speak of a complete know- 

 ledge of the minuter structure of animal.* in general, we ore not 

 acquainted with the structure of a sin . not 



ii "f man, although be box ,uently tlie olject of in 



gntidii ; and therefore it has hitherto i. . M m p. .;.:, to l.nn.' the 

 essentially nearer its goal. It would however be unj 

 I. and depreciate what we do possess ; and it may at any rate 

 be said that we have acquired a rich store of fact*, and a few more 

 trustworthy propositions. To indicate only tho more important of 

 the former, it may be mentioned that we have a very MI; 

 acquaintance with the perfect elementary parts of the higher animals; 

 and that we also understand their development, with the exception 

 of tbe elastic tissue, and of the elements of the teeth and bones. 

 The mode in which these are united into organs has been less exa- 

 mined ; yet on thi* head also much has been added of late, especially 

 in man, whose individual organs, with the exception of the nervous 

 system, the higher organs of sense, and a few glands (the liver, blood- 

 vascular glands), have been almost exhaustively investigated. If 

 the like progress continue to be made, the structure of the human 

 body will iu a few years be so clearly made out that, except pcrhap* 

 in the nervous system, nothing more of importance will remain to be 

 done with our present modes of investigation. With Comparative 

 Histology it i* otherwise : hardly commenced, not yean but decades 

 will be needed to carry out tbe necessary investigations. Whoever 

 will do good work in thi* field must, by monographs of typical forms 

 embracing their whole structure from the earliest periods of develop- 

 ment, obtain a general view of all the divisions of the animal kin 

 and then by '.ho method* above described strive to develop their 

 laws. 



" As regards the general propositions of Histology, the science has 

 made no important progress since Schwann ; however, much has been 

 attained by the confirmation of tbe brood outlines of hi doctrines. 

 The position, that all tho higher animals at one time consist wholly 



