The Bridgewater Treatises
on the Power, Wisdom, and Goodness of God,
As Manifested in the Creation.

___________

Treatise V.

ANIMAL AND VEGETABLE PHYSIOLOGY, CONSIDERED

WITH REFERENCE TO NATURAL THEOLOGY.

BY

PETER MARK ROGET, M. D.

Secretary to the Royal Society, Fullerian Professor of Physiology in the
Royal Institution of Great Britain, Vice President of the Society
of Arts, Fellow of the Royal College of Physicians,
Consulting Physician to the Queen Charlotte's
Lying-in Hospital, and to the Northern
Dispensary, ETC,ETC.


In Two Volumes

[SECOND EDITION]

VOLUME II.


logo

PHILADELPHIA

Lea & Blanchard,

1839.


This electronic edition prepared by Dr. David C. Bossard
from original documents in his personal library.

October, 2006.

Copyright © 2006 by David C. Bossard.

LIST OF ENGRAVINGS
VOLUME I.  xix.   xix  xx  xxi  xxii  xxiii  xxiv
VOLUME II. xxv.-xxx.   xxv  xxvi  xxvii  xxviii  xxix  xxx

NOTE:  Text images have a resolution of 100 ppi. High resolution images (400 ppi) are available here.

CONTENTS.

PART II. THE VITAL FUNCTIONS.

CHAPTER I. -- OBJECTS OF NUTRITION.

9.  009  010  011  012  013  014  015  016  017  018

[009] THE mechanical structure and properties of the organized fabric, which have occupied our attention in the preceding volume, are necessary for the maintenance of life, and the exercise of the vital powers. But, however artificially that fabric may have been constructed, and however admirable the skill and the foresight which have been displayed in ensuring the safety of its elaborate mechanism, and in preserving the harmony of its complicated movements, it yet of necessity contains within itself the elements of its own dissolution. The nimal machine, in common with every other mechanical contrivance, is subject to wear and deteriorate' by constant use. Not only in the greater movements of the limbs, but also in the more delicate actions of the internal organs, we may trace the operation of many causes inevitably leading to their ultimate destruction. ... Provision must accordingly be made for remedying these constant causes of decay by the supply of those peculiar, materials which the organs require for recruiting their declining energies. ...[012] We may take as an example one of the simplest of organic products, namely, Sugar; a substance which has been analyzed with the greatest accuracy by modern chemists: yet to reproduce this sugar, by the artificial combination of its simple elements, is a problem which has hitherto baffled all the efforts of philosophy. [Note: The complex sucrose cycle was first described in the 1960s, 130 years after this writing -- dcb]

[012] The elements of organic substances are not very numerous: the principal of them being oxygen, carbon, hydrogen, nitrogen, sulphur, and phosphorus, together with a few of the-alkaline, earthy, and metallic bases. These substances are variously united, so as to form certain specific compounds, which, although they are susceptible, in difibrent instances, of endless modifications, yet possess such a general character of uniformity, as to allow of their being arranged in certain classes; the most characteristic substance in each class constituting what is called a proximate organic principle. Thus, in the vegetable kingdom we have Lignin, Tannin, Mucilage, Oil, Sugar, Fecula, &c. The animal kingdom, in like manner, furnishes Gelatin, Albumen, Fibrin, Mucus, Entomoline, Elearin, Stearin, and many others.

[013] This peculiar mode of combination gives rise to a remarkable condition, which attaches to the chemical properties of organic compounds. The attractive forces, by which their several ingredients are held together, being very numerous, require to be much more nicely balanced, in order to retaim them in combination. Slight causes are sufficient to disturb, or even overset, this equipoise of affinities, and often produce rapid changes of form, or even complete decomposition. The principles, thus retained in a kind of forced union, have a constant tendency to react upon one another and to produce, from slight variations of circumstances, a totally new order of combinations. Thus, a degree of heat which would occasion no change in most mineral substances. will at once effect the complete disunion of the elements o an animal or vegetable body. Organic substances are, in like manner, unable to resist the slower, but equally destructive agency of water and atmospheric air; and they are also liable to various spontaneous changes, such as those constituting fermentation and putrefaction, which occur when their vitality is extinct, and when they are consequently abandoned to the uncontrolled operation of their natural chemical affinities. This tendency to decomposition may, indeed, be regarded as inherent in all organized substances, and as requiring for its counteraction, in the living system, that perpetual renovation of materials which is supplied by the powers of nutrition. [emphasis added -- dcb] ... [014] Hence, the continued interchange and renewal of particles which take place in the more active organs of the system, especially in the higher classes of animals. In the fabric of those animals which possess an extensive system of circulating and absorbing vessels, the changes which are effected are so considerable and so rapid, that even in the densest textures, such as the bones, scarcely any portion of the substance which originally composed them is permanently retained in their structure. To so great an extent is this renovation of materials carried on in the human system, that doubts may very reasonably be entertained as to the identity of any portion of the body after the lapse of a certain time. The period assigned by the ancients for this entire change of the substance of the body, was seven or eight years: but modern inquiries, which show us the rapid reparation that takes place in injured parts, and the quick renewal o1 the bones themselves, tend to prove that even a shorter time than this is adequate to the complete renovation of every portion of the living fabric.

[015] Imperfect as is our knowlcdgc of organic chemistry, we see enough to convince us that a series of the most refined and artificial operations is required, in order to bring about the complicated and elaborate arrangements of elements which constitute both animal and vegetable products. Thus, in the very outset of this, as of every other inquiry in Physiology, we meet with evidences of profound intention and consummate art, infinitely surpassing not only the power and resources, but even the imagination of man [emphasis added].


CHAPTER II. -- NUTRITION IN VEGETABLES.

1.  Food of Plants.  19  019  020  021
2. Absorption of Nutriment by Plants.  21  021  022  023  024  025  026  027
3. Exhalation.  27  027
4. Aeration of the Sap.  28  028  029  030  031  032

[028] The remarkable discovery that oxygen gas is exhaled from the leaves of plants during the day time, was made by the great founder of pneumatic chemistry, Dr. Priestly. ... Solar light is an essential agent in effecting this....

[030] During the whole of the night, the same leaves, which had been exhaling oxygen during the day, absorb a portion of that element. The oxygen thus absorbed enters immediately into combination with the carbonaceous matter in the plant, forming with it carbonic acid. ...

This reversal at night of what was done in the day may, at first sight, appear to be at variance with the unity of plan, which we should expect to find preserved in the vegetable economy; but a more attentive examination of the process will show that the whole is in perfect harmony, and that these contrary processes are both of them necessary, in order to produce the result intended.

The water which is absorbed by the roots generally carries with it a certain quantity of soluble animal or vegetable materials, which contain carbon. This carbon is transmitted to the leaves, where, during the night, it is made to combine, with the oxygen they have absorbed. It is thus converted into carbonic dcid, which, when daylight prevails, is decomposed; the oxygen being dissipated, and the carbon retained. It is evident that the object of the whole process is to obtain carbon in that precise state of disintegration, to which it is reduced at the moment of its separation from carbonic acid by the action of solar light on the green substance of the leaves; for it is in this state alone that it is available in promoting the nourishment of the plant, and not in the crude condition in which it exists when it is pumped up from the earth...

[032] Thus are the two great organized kingdoms of the creation made to co-operatein the execution of the same design; each ministering to the other, and preserving that due balance in the constitution of the atmosphere, which adapts it to the welfare and activity of every order of beings, and which would soon be destroyed, were the operations of any one of them to be suspended. It is impossible to contemplate so special an adjustment of opposite effects without admiring this beautiful dispensation of Providence, extending over so vast a scale of being, and demonstrating the unity of plan on which the whole system of organized creation has been devised.

5. Return of the Sap.  32  032  033  034  035  036  037  038
6. Secretion in Vegetables.  38   038  039  040  041  042  043
7. Excretion in Vegetables.  43   043  044  045  046  047

CHAPTER III. -- ANIMAL NUTRITION IN GENERAL.

1. Food of Animals.  47 047  048  049  050  051  052  053  054  055
2. Series of Vital Functions.  55   055  056  057

CHAPTER IV. -- NUTRITION IN THE LOWER ORDERS OF ANIMALS.

58.   058  059  060  061  062  063  064  065  066  067  068  069  070  071  072  073  074  075  076  077  078  079  080

CHAPTER V. -- NUTRITION IN THE HIGHER ORDERS OF ANIMALS.

80.   080  081  082  083  084  085  086

CHAPTER VI. -- PREPARATION OF FOOD.

1.  Prehension of Liquid Food.  86   086  087  088  089
2.  Prehension of Solid Food.  89   089  090  091  092  093  094  095  096  097  098  099  100  101  102  103  104
3.  Mastication by means of Teeth. 104   104  105  106  107  108  109  110  111  112  113  114
4.  Formation and Development of the Teeth.  114   114  115  116  117  118  119  120  121  122
5.  Trituration of Food in Internal Cavities.  122   122  123  124  125  126  127
6.  Deglutition.  127  127  128  129  130
7.  Receptacles for retaining Food.  130   130  131

CHAPTER VII. -- DIGESTION.

132.   132  133  134  135  136  137  138  139  140  141  142  143  144  145  146  147

CHAPTER VIII. -- CRYLIFICATION.

148.   148  149  150  151  152  153  154  155  156  157  158  159  160  161  162  163

CHAPTER IX. -- LACTEAL ABSORPTION.

164.   164  165  166  167

CHAPTER X. -- CIRCULATION.

1. Diffused Circulation.  167   167  168  169  170
2. Vascular Circulation.  170   170  171  172  173  174  175  176  177  178  179  180  181  182  183  184  185  186  187  188  189  190  191
3. Respiratory Circulation.  191  191  192  193  194  195  196  197  198  199  200  201
4. Distribution of Blood Vessels.  201  201  202  203  204  205  206  207

CHAPTER XI. -- RESPIRATION.

1.  Respiration in general.  208  208  209  210
2.  Aquatic Respiration.  210   210  211  212  213  214  215  216  217  218  219  220  221
3.  Atmospheric Respiration.  221   221  222  223  224  225  226  227  228  229  230  231  232  233  234  235  236
4.  Chemical Changes effected by Respiration.  236   236  237  238  239  240  241  242  243

CHAPTER XII. -- SECRETION.

243.   243  244  245  246  247  248  249

CHAPTER XIII.  -- ABSORPTION.

250.   250  251  252

CHAPTER XIV. -- NERVOUS POWER.


252.   252  253  254  255  256  257

PART III. THE SENSORIAL FUNCTIONS.


CHAPTER I.  -- SENSATION.

258.   258  259  260  261  262  263  264  265  266  267

CHAPTER II.  -- TOUCH.

268.   268  269  270  271  272  273  274  275  276  277  278

CHAPTER III.  -- TASTE.

279.   279  280  281

CHAPTER IV.  -- SMELL.

281.   281  282  283  284  285  286  287  288  289  290  291  292  293

CHAPTER V.  -- HEARING.

1.  Acoustic Principles.  294   294  295  296  297
2. Physiology of Hearing in Man.  298   298  299  300  301  302  303  304  305  306  307  308
3. Comparative Physiology of Hearing.  308   308  309  310  311  312  313  314  315

CHAPTER VI.  -- VISION.

1. Object of the Sense of Vision.  315   315  316  317  318
2. Modes of accomplishing the objects of Vision.  318   318  319  320  321  322  323  324  325
3. Structure of the eye.  325   325  326  327  328  329  330  331  332
4. Physiology of Perfect Vision.  332   332  333  334  335  336  337
5. Comparative Physiology of Vision.  337   337  338  339  340  341  342  343  344  345  346  347  348  349  350  351  352  353  354  355  356  357

CHAPTER VII.  -- PERCEPTION.

358.   358  359  360  361  362  363  364  365  366  367  368  369  370  371  372  373  374  375  376  377

CHAPTER VIII.  -- COMPARATIVE PHYSIOLOGY OF THE NERVOUS SYSTEM.

1. Nervous System of Invertebrated Animals.  378  378  379  380  381  382  383  384  385  386  387  388
2. Nervous System of Vertebrated Animals.  388   388  389  390  391  392  393  394  395
3. Functions of the Brain.  395   395  396  397  398
4. Comparative Physiology of Perception.  398   398  399  400  401  402  403  404  405  406  407

PART IV. THE REPRODUCTIVE  FUNCTIONS.


CHAPTER I.  -- REPRODUCTION.

408.   408  409  410  411  412  413  414  415  416  417  418  419

CHAPTER II.  -- ORGANIC DEVELOPMENT.

420.   420  421  422  423  424  425  426  427  428  429  430  431  432

CHAPTER III.  -- DECLINE OF THE SYSTEM.

433.   433  434  435  436

CHAPTER IV.  -- UNITY OF DESIGN.

437.   437  438  439  440  441  442  443  444  445  446  447  448

[440 - Early concept of "recapitulation"] It is remarked, in farther corroboration of these views, that the animals which occupy the highest stations in each series possess, at the commencement of their existence, forms exhibiting a marked resemblance to those presented in the permanent condition of the lowest animals in the same series; and that, during the progress of their development, they assume, in succession, the characters of each tribe, corresponding to their consecutive order in the ascending chain; so that the peculiarities which distinguish the higher animal, on its attaining its ultimate and permanent form, are those which it has received in its last stage of embryonic evolution. ... [443] Nor is the human embryo exempt from the same metatnorphoses, possessing, at one period, branchiae and branchial apertures similar to those of the cartilaginous fishes, a heart with a single set of cavities, and a brain consisting of a longitudinal series of tubercles; next losing its branchiae, and acquiring lungs, while the circulation is yet single, and thus imitating the condition of the reptile; then acquiring a double circulation, but an incomplete diaphragm, like birds; afterwards, appearing like a quadruped, with a caudal prolongation of the sacrum, and an intermaxillary bone; and, lastly, changing its structure to one adapted to the erect position, accompanied by a great expansion of the cerebral hemispheres, which extend backwards so as completely to cover the cerebellum. Thus does the whole fabric arrive, by a gradual process of mutation, at an extent of elaboration and refinement, which has been justly regarded as constituting a climax of organic development, unattainable by any other race of terrestrial beings. ... It must, I think, be admitted that the analogies, on which the hypothesis in question is founded, are numerous and striking; but great care should be taken not to carry it farther than the just interpretation of the facts thethselves may warrant. It should be borne in mind that these facts are few, compared with the entire history of animal development; and that the resemblances which have been so ingeniously traced, are partial only, and fall very short of that universality, which alone constitutes the solid basis of a strictly philosophical theory. Whatever may be the apparent similarity between one animal and another, during different periods of their respective developments, there still exist specific differences, establishing between them an impassable barrier of separation, and effectually preventing any conversion of one species into another, however nearly the two may be mutually allied. The essential characters of each species, amidst occasional varieties, remain ever constant and immutable. Although gradations, to a greater or less extent, may be traced among the races both of plants and animals, yet in no case is the series strictly continuous; each step, however short, being in reality an abrupt transition from one type of conformation to another. In many instances the interval is considerable; as, for example, in the passage from the invertebrate to the vertebrated classes; and, indeed, in every instance where great changes in the nature and arrangement of the functions take place.

INDEX 
449   449  450  451  452  453  454  455  456  457  458  459  460  461  462  463