We will stake our chance of immortal fame against a small portion of the legal currency, that these were the associations which suggested Trapp's excuse-"All the parties are disposed of, myself, my sister, and the world; they must be reserved topics; on whom, then, am I to rely? Is there any one else implicated in that d-d drawing-room affair? The dog! the dog forced into this scrape. Why might not the dog help us out of it? The dog shall serve my turn; let him limp through it as he may, and be hanged to-morrow, if necessary, to corroborate my story." I do not say that this was the precise train and wording of this extempore pretext, but that it was a similar chain of ideas, evincing considerable analytical talent in Trapp, who, in reply to the iterated question what his business was, bolted out the following words:

"My business is-a-one of anxiety-a-but I beg you will nota-alarm yourself unnecessarily. The dog-a-has shown-a-symptoms of madness,-a-and I could not rest satisfied until I had satisfied myself of the state of your-a-hand. That's all.”

Debonair sprang from his seat like an enraged whig; for though he was a good-natured man, he had none of the facility which is attributed to that character, of being gulled by a paltry evasion: he rose in a passion, and actually premeditated the execution of Trapp's worst fears. Trapp, too, had started up, to avoid being taken at a disadvantage; but a sudden flood of dignity rising above Sam's ire, he politely pointed to a chair, and said, "Pray be seated, Mr. Trapp; collect yourself a little; I am quite disposed to yield you a patient hearing. If you have any explanation to demand, pray come to it at once; you cannot possibly have sought me solely with the view you mention?"—" Solely, upon my honour," answered Trapp, deceived by the mildness of the foregoing tones into an idea that he had imposed upon the speaker, whose intellect he had undervalued, for reasons before adduced. Sam immediately added,

"Then it is the most execrable subterfuge I have ever heard, and your impertinence is inexcusable. I renounce your acquaintance entirely, sir, after this paltry conduct; and, to prevent my terminating it in the proper way, withdraw, sir, instantly."

The whole infinitive limb of this speech sounded like nothing but stairs and windows on Trapp's tympanum. And though the indicative and imperative were mighty harsh moods, as here used, still the alternative between walking gently through a door, or flying, sans parachute, through a window; between descending, step by step, a staircase, and being tumbled headlong down the same, was not, in his opinion, to be rashly rejected; besides, the affront in the noxious. clauses might be as well noticed to-morrow, in a week, a month, or never, if Debonair never recovered his footing in society. He, therefore, availed himself of the permission given him, and sneaked out of the door, cursing the audacity which he had mistaken for courage, and half misdoubting in his heart that he was both a coward and a rascal.

To these conscious characteristics he added that of a mean reporter of what he had seen, and what he had not said nor done. In consequence of which Debonair was irrevocably banished from his circle, if their coldness had not already placed polar barriers between him and

them. They had exiled him on suspicion, because they could not find out who he was; and, instead of revising, they sanctioned anew the sentence when they discovered the whole truth of their prying query.

That it was a most unjust post facto law, made for his particular case, to punish him for having once committed the error of forming intimacies with a heartless people, is unquestionable; but it is not near so certain that the greater severity of the sentence has not fallen upon the judges rather than upon the judged: and that numbers have not, long ere this, missed Debonair's power of amusing infinitely more than he ever can have missed their complaisance and mahogany tables.

MINIMUM.

DR. SOUTHWOOD SMITH'S LECTURES,

ON

COMPARATIVE AND HUMAN PHYSIOLOGY.

[According to our promise, we return to our task of reporting the opinions, and the accumulated information, of these very interesting lectures.]

AFTER having stated the phenomena which are peculiar to life, and which constitute it, Dr. Smith proceeded to point out the characters which distinguish animal from vegetable life. He showed that

the animal possesses two faculties of which the vegetable is destitute: that the phenomena of life are precisely the same in both these classes of living beings, up to a certain point: but that beyond that point the animal indicates two additional phenomena, of which there is no manifestation in the plant.

It was next observed, that the possession of these additional faculties necessarily modifies the whole economy of the being to whom they are communicated; and that all the varieties of organization by which the animal is distinguished from the vegetable, and by which one animal is distinguished from another, are the result of adaptations which are indispensably required to adjust the conditions of life in general, to the conditions of animal life in particular. As this modification of the general functions of life, by the communication of the special functions of animal life, is one of great interest, we shall follow Dr. Smith through the illustrations he gave of this subject, especially as the manner in which this was done led him to exhibit a general view of the organs and functions of the animal body.

It was stated, that the structure of vegetables is remarkably uniform in external configuration, and in sensible properties, they differ much from each other; but in structure, the similarity of this whole class is striking. In animals, the diversity of structure in the different tubes is infinite; and that diversity, in external configuration, is in general connected without very important differences in internal structure: the external diversity is indeed the result of the internal organization. The simple structure of the vegetable, adequate to its simple functions, allows of uniformity in the organization of the class : the complicated faculties of the animal require numerous and complicated organs.

The vegetable is fixed to one spot: the materials adapted to its

nourishment are contained in the soil: its roots are the organs by which its nutricient matter is absorbed: hence it must always be in contact with its nutricient matter, and can therefore need no organs for containing it. But animals are not attached to the soil: they possess the property of locomotion: in beings thus constituted, it is not possible that their nourishment should be absorbed from the earth. The addition of this faculty of locomotion, renders a modification of that of nutrition indispensable. Beings which continually change their place, must be provided with the means of transporting, along with themselves, the nutriment necessary for their support. In general, that provision is made by furnishing them with an internal cavity, within which they deposit the substances prepared for their nourishment. In the coats which form the walls of this cavity, are placed the orifices of vessels which absorb the nutritive particles. This cavity with its contents, is to the animal what the soil is to the vegetable: its absorbing vessels constitute, in the expressive language of Boerhaave,, the internal roots of the animal.

Many of the lower tribes of animals, those especially which inhabit water, and derive their nourishment from the vegetable and animal matter held in solution by this fluid, (for it is an error to suppose that any animal is nourished by pure water alone,) are, in this respect, in circumstances precisely similar to the vegetable. They are constantly in contact with the nutricient particles from which they derive their sustenance. Accordingly they are furnished with no internal cavity for containing their food. They are composed of a gelatinous homogeneous mess, the porous texture of which is endowed with the property of imbibing from the surrounding element the nutricient particles necessary to maintain its integrity. Of these animals, the most simple consist of this gelatinous substance alone, without any other organs whatever, which we have the means of detecting: in the ascending scale, various appendages are added, which constitute distinct external organs; and at length the more compound are furnished with tentaculæ, special instruments, by means of which their nourishment is apprehended, and which possess a very striking analogy to the roots of plants.

But in the higher classes, not only is an internal cavity provided for containing its nutritive matter, but that cavity is of sufficient magnitude to admit solid substances. At this point, nutrition ceases to be the mere imbibition of sustenance from the soil or the atmosphere. Preparatory operations are now necessary to apprehend the food, to divide it, and to fit it, in various modes, for its common receptacle. These operations, together with the changes which the aliment undergoes in its receptacle, constitute a process: that process is termed digestion. Thus digestion is a modification of the function of nutrition, peculiar to animals, and rendered indispensable by the faculty of locomotion.

A second modification, equally indispensable, arises out of the necessity of conveying the nutritive matter to different parts of the body. In the animal, in consequence of the greater complexity of its organization, a greater force is required than is necessary in the vegetable, to propel the nutritive fluid over its extended surface, and into its various passages and cavities. There must be a circulation of the

nutritive fluid; consequently, vessels must be furnished to contain the fluid: an engine must be constructed capable of generating a force adequate to communicate to it the requisite impulse. Thus, a circulation with the organs necessary to perform the function constitutes a second complication, strictly though remotely connected with the communication of voluntary motion.

A third complication is rendered indispensable by the second. The circulation distributing the nutritive fluid to every part of the body, and depositing every where the nutritive particles as they are needed, to repair the waste of the system, means must be procured to supply the nutritive fluid with fresh matter. For this object the digestive organs are provided. Between the digestive organs, and the vessels which carry on the circulation, there must therefore be a communication. That communication is established by a system of vessels termed absorbents. At one extremity the absorbents are in communication with the intestines, the organs which contain the newly formed nutritive matter, which they absorb by innumerable orifices; at the other extremity they are in communication with one of the main trunks of the circulating system, into which they pour the digested aliment received from the organs that prepare it. In this manner a direct communication is established between the great laboratory, in which the nutritive matter is prepared, and the vessels by which that matter is conveyed to the different parts of the body. Thus the absorbent system is a mere complication of the animal organization, rendered indispensable by that of the circulation.

But the aliment, after it has undergone all the operations to which it is subjected in the digestive organs, is still not fit for the purpose of nutrition. A process, by which its heterogeneous particles are converted into one common nature, and which is termed assimilation, is performed by any organized body. There is no example of life, animal or vegetable, in which this process does not take place. The function by which it is affected is termed respiration. Respiration, performed in some mode, is indispensable to life, because it is an essential part of the function of nutrition. The actual mode in which it is effected in any given instance entirely depends on the mode of life of the individual. In the vegetable there is no proper circulation; therefore, the whole external surface of the plant is made one continuous organ of respiration. In the lower tribes of animals there is no circulation in the lowest, respiration is performed just as it is in the vegetable, by the whole of their external surface; in animals somewhat higher in the scale, peculiar vessels are provided for this purpose, by means of which air is conveyed into every part of their body. Then, whenever there are distinct vessels and a proper circulation, there a peculiar organ is provided for the function of respiration. General circulation-respiration by a special organ-are correlative conditions from which there is no duration in the whole extent of the animal creation, and for the latter of which a necessity is created by the former.

Thus we perceive here the communication of one subordinate faculty, that of locomotion, necessarily modifies the general faculty of nutrition, by creating the necessity for numerous subordinate expedients in order to complete it. A third modification arises out of a

second, and a fourth out of a third. Whether the conformation of an animal be simple or complex, its structure is in invariable and strict accordance with its mode of life. It follows that there is no such thing in the animal creation as an arbitrary disposition of parts; that no organ is communicated unless there exist for it an absolute necessity; that no organ is withheld which is requisite to the convenience of the animal, in the condition in which it is placed. It is in the true spirit of physiology to point out and insist on the wisdom, and beauty, and beneficence of such adjustments.

The functions which are indispensable to animal existence are those of nutrition, circulation, absorption, respiration, reproduction, sensation, and voluntary motion.

In the lowest tribes of animals no distinct organs are provided for the performance of these different functions, at least none that can be discovered. The substance of which their body is composed appears to be entirely homogeneous. The lowest species of animalculi consist of a single globule, which looks like a minute drop of jelly; yet that globule, besides exercising all the functions of the vegetable, is unquestionably endowed with the power of motion; as far as we are capable of judging, that motion is spontaneous, and if so, it must be the result of sensation. The lower tribes of zoophytes, those, for example, which consist of an homogeneous substance similar to jelly, are without any distinct vessel or organ; they are unquestionably capable of performing all the vegetative functions; they seem to be endowed with some degree of spontaneous motion, though slight: in all those cases one and the same substance must be conceived to perform functions extremely different. In by far the greater number of animals, however, for every distinct function there is provided a separate

organ.

Some species of animalculi are composed of a simple sac, with an aperture at one extremity. In this structure there is no distinct apparatus for digestion; yet since the internal surface of this sac is capable of digesting food, it must be considered as the first trace of an alimentary tube; as a stomach in the most simple form in which that organ can exist. It is the same with the gelatinous zoophytes; being without any distinct apparatus for digestion, the entire substance of the body must be regarded as a stomach.

In the higher classes a distinct organ is provided for the function of digestion. Sometimes it consists of a sac open at both extremities; sometimes of an elongated tube; in the highest classes, of both united. In every different species the sac varies in capacity; the tube differs in length, width, and convolutions. The principal dilutative of the sac is termed the stomach; sometimes there are more dilutations than one; then there are said to be two or more stomachs: that part of the tube below the stomach is denominated the intestine; the whole of the tube, from one extremity of the organ to the other, is called the alimentary canal.

In general this organ is composed of separate coats, the internal of which is commonly a continuation of the external covering of the body. Hence the external and internal surface of the animal body is in general composed of the same tissue, and modified in adaptation to its specific function, but both essentially the same.