inexhaustible. Knowledge unfolds vista after | whether it can digest? Have not you yourvista, forever stretching illimitably distant, self repeatedly fed these animals with limthe horizon moving as we move. New facts pets and cooked beef? are they not greedy of connect themselves with new forms; the such food? It is perfectly true. Neverthemost casual observation often becomes a less a doubt occurred to me whether they did spark of inextinguishable thought running really digest, in any proper sense of the along trains of inflammable suggestion. To term; and I made a note of the doubt, as this intent the naturalist should always have of a point to be investigated immediately on pencil and note-book on his working-table, in my arrival at the coast. Experiment should which to record every new fact, no matter settle the doubt. Before narrating the exhow trifling it may seem at the moment; the periments, it will be needful to settle with time will come when that and other facts the reader a few generalities on the subject will be the keys to unlock many a casket. of digestion; since, in point of fact, the inNot that Observation alone is, as many im-terest of the question falls mainly on the agine, the potent instrument of Zoology. general subject, and only with a secondary Lists of details crowd books and journals, importance on the digestive powers of the yet these are in themselves no better than the Anemones. observations of Chaldean shepherds, which What are we to understand by Digestion? produced no Astronomy in centuries of watch- At first the question seems so easy; yet the ing. They find their place in science, only closer it is investigated, the remoter as the architectural mind disposes them in seems the possibility of answering it. due co-ordination. What should we think of a Let us make a clearance by first discriminatchemist who, on mere inspection of substances, ing Digestion-as a special function of the unaided by re-agents, and his balance, hoped intestinal canal-from Assimilation, which to further Chemistry? What would lists of is the general property possessed by all living such observation avail? And in the far more tissues. For an animal to grow, and to complex science of Biology, how shall cursory repair the waste which the action of life ininspection, superficial observation, avail? We cessantly produces, it must assimulate, must follow the Methods which have led to cer- which, as the word implies, means to separtainty in the exact sciences. We must ren-ate from the external medium such subder the complex facts of Life as simple as stances as are like to its own substance, or we can, by processes of elimination. Exper- can be converted into them by the vital iment must go hand in hand with Observation, controlling it, and assuring us that we have correctly observed. Much has been done, and is daily done, in this way, yet still men too easily content themselves with observation, or, what is equally fallacious, with anatomical deduction, declaring an organ to have such or such a function merely because it resembles an organ known to have the function;t when in most of these cases, direct experiment would show the error of the conclusion. In former papers I have illustrated this point, and have again to do so apropos of the digestive power of the Sea Anemones.

In my note-book is penciled this brief query, "Do the Actinia digest at all?" a doubt which, in its naked simplicity, might rouse contempt in the mind of any zoologist accidentally reading it. What! here is animal notoriously carnivorous, and you ask

† On this point, see the luminous Lecons de Physiologie Experimentale of Claude Bernard, vol. ii.

chemistry, rejecting all such as are unlike, or not convertable. Very simple organisms find assimilable food in the element they live in, and the process of separation is easy: they have no stomach, not even a mouth, much less glands secreting solvent fluids. Very complex organisms, on the contrary, do not, in the air they breathe, or on the earth they tread, find the variety of substances necessary to build up their bodies; the substances have to be sought, captured, and when found, are not found in an assimilable condition, but in a condition requiring great changes, mechanical and chemical, before they are able to enter into the construction of the tissues.

An example will make this plain: Let us first consider the process in the Actinophrys, a microscopic animal carefully studied by Kölliker. It is a mere mass of jelly-like substance, very contractile, without the

*Siebold . Kölliker's Zeitschrift für Wissens chaftliche Zoologie, 1, 198.

slightest trace of organs, without even a nates, so is this blood-formation but the distinct envelope separable from the mass. commencement of a new series of changes, The outer layer is formed into long tentacu- and these the most important. I think it lar filaments, which, like the tentacles of a polype, seize hold of young animalcules, or even minute crustaceans. The resemblance to the polype is carried further: no sooner does one of the filaments seize a prey than it retracts; all the others round it bend their points over the captive, and gradually enclose it; they then retract, and bring the food in contact with the body of the animal. The point of contact is next seen to yield inwards, retracting as the filaments had retracted, and, as it deepens, the food sinks into the substance of the body, the edges of the cavity closing over it. In the centre of the body the soluble parts are dissolved, the body having resumed its original appearance. This done, the insoluble parts make their way out, much as they made their way in; and thus the whole process of ingestion and egestion is accomplished.

can be shown that the blood itself is not more immediately and directly assimilable than the mutton chop from which it was formed. In its passage through the walls of its vessels, it undergoes specific changes, fitting it for assimilation; without such changes it is not assimilable; blood, as blood, nourishes no tissue, but lies on it like any other foreign substance which must be got rid of by reabsorption into the veins as we see when a vessel is ruptured, and the blood gets deposited in the parenchyma. Blood is, in fact, as Bergmann and Leuckart well express it, "a depôt of assimilable and secretory substances; and its purpose in the economy is that of a regulating apparatus, which is necessitated by the fluctuations in the procuring of food." *

Remember also, that before Assimilation can take place, the food must be rendered soluble. Solubility is a primary condition,

stances have to undergo chemical changes, both of decomposition and allotropism, before they form parts of the living body. If albumen or sugar be injected into the veins, they will not be assimilated, but cast out unaltered in the excretions; whereas, if injected into the alimentary canal, or into the portal vein, which would carry them through the laboratory of the liver, they are entirely assimulated.

We need not pause to trace the episodes of the complex story of digestion in the higher but not the only one. Many soluble subanimals, episodes of mastication, insalivation, chymification, chemical transformations aiding mechanical actions; every one is familiar with the general facts. Let us only note that even milk, which contains all the substances needed for the nourishment of the child, contains them in a condition perfectly useless, as far as the direct and immediate nourishment of the child is concerned until the milk has undergone the digestive process, namely, a succession of Thus we see that solubility and transformchemical decompositions and recompositions, ation are the two digestive effects, to produce it is no more competent to nourish the mus- which, two agencies are needful, the mechancles, bones, and nerves of the child, than so ical and chemical. From these two points much chalk and water, which is delusively all other questions expansively radiate, to sold as milk in virtuous cities. The mutton them they all converge. A single fact strikchop, too, which we justly reckon such ex-ingly impresses the mind with a sense of the cellent food, is only "food potential; " it extent to which chemical agency reaches, must undergo a very curious series of namely, that in the course of four-andchanges before it can be converted into twenty hours a sixth part of the whole blood. Nor is the business finished there. We are erroneously accustomed to consider blood as the final stage of food, previous to its assimulation. Physiologists trace the story of digestion up to this point, and there leave it; as story-writers leave their heroes married, thereby indicating that nothing more remains to be said. But just as marriage is the beginning of a new act in the drama, and the act in which all life culmi

weight of the body is poured into the alimentary canal, under the form of varions secretions. Much more fluid is secreted from the blood and poured into this canal during a single day, than would make up the whole mass of fluid circulating in the bloodvessels at any given period.t

Vergleichende, Anatomie und Physiologie, p. t Lehmann: Lehrbuch der Physiol. Chemie. III.

164.

226, 2d edit.

The reader's attention has been so fully ascending series, inasmuch as the simpler directed to this twofold agency of Digestion, animals have not the special functions of and especially to its chemical agency, that a more complex animals, we must deny to the clear view may be taken of the question two first classes of M. Bernard's series, any which must arise as to what, in the ab- such special function as Digestion, and constract, is the purpose of Digestion. In the fine it to the third class. We do not, except abstract we may declare it to be the prepar- in loose latitude of phrase, speak of the legs ation of the food, rendering it fitted for of an animalcule, meaning its organs of Assimilation. But if we descend from progression; because a leg is a specific organ heights of abstraction, and approach con- of progression, uniform in its elements crete questions, we soon find this answer throughout the series of animals possessing including several processes-such as the pre-legs; nor should we, otherwise than in easy hension and mastication of food, its absorp-speech, talk of the digestion of a polype, tion and circulation, its aeration in the meaning thereby its nutrition. The purpose blood, and finally, its transudation through of a leg, progression, is fulfilled by the cilia the walls of the capillaries-none of which which move the animalcule; the purpose of can, without great impropriety, be called digestion, preparation of food, is performed digestive. We must be more specific. No by the cavity of the polype; but the specific man would confound mastication with organs, named legs and alimentary canal, digestion, or circulation with digestion; and and the specific functions of those organs, we must therefore limit the term digestion walking and digestion, are in both cases to some specific meaning; mastication is the absent. special function of the jaws, circulation of the vessels, respiration of the lungs, and digestion of the alimentary canal. But even this is too vague for our purpose; we must affix a still more specific character to Diges-ing food, but only of their power of chemition; and this may be expressed in the following formula: That, and that only, is a specifically digestive act which takes place in an alimentary canal, by means of secretions capable of chemically modifying the food, so as to prepare it for Assimilation.

If the reader has followed me thus far, he will have understood that, when I doubted whether the Actinia digested, there was no doubt entertained of their power of prepar

cally digesting it. I doubted, in short, whether they should not be separated from the more complex animals which digest, and whether they should not rank in M. Bernard's second class. We do not call a hut or group of cottages a city. We do not The preparation of food we have seen to speak of its commerce, its government, its be both mechanical and chemical, but I literature; these are social functions develselect the latter as the specific characteristic oped in a complex city, not possible in a of the digestive process, in order to prevent group of cottages. In the same way we confusion. Claude Bernard says: "We can should not expect to find digestion, respiraconceive an animal without any digestive tion, sensation, or any other complex result, apparatus, mechanical or chemical, because in animals so simple as a Sea Anemone. living in an element which furnishes nutri- Nor could the notion ever have gained curtive material directly; we can also conceive rency, had there been the proper precision the digestive act reduced to a simple me- in our zoological language, and had not the chanical apparatus which has to press out" fallacy of observation" misled us. certain alimentary juices capable of nourish- Now to the experiments. The first point ing the tissues without undergoing chemical to be settled was this: Have the Polypes any modifications; but usually the digestive act thing of the nature of a solvent fluid secreted is composed of two orders of phenomena, by their stomachs? "It is obvious," says physical and chemical." * This is a brief Dr. Carpenter, the latest writer on this suband luminous classification as regards the ject," that a powerfully solvent fluid is whole animal series, and it well expresses the secreted from the walls of the gastric cavity; ascending complexity of that series; but inasmuch as special functions only make their appearance at certain stages of that *Lecons de Physiol, Expérimentale, 11. 490.

for the soft parts of the food which is drawn into it are gradually dissolved, and this without the assistance of any mechanical trituration." 17 Obvions, indeed, the fact

seems, until it is interrogated a little more ing that a solvent fluid had penetrated the closely, and then we find, 1st, that no sol- holes, and dissolved the meat. I took a vent fluid is secreted; 2d, that the food is piece of quill, of about half an inch in not dissolved; but only the juices pressed length, open at both ends, and having six out. My first experiment was to test the good openings cut in the sides, thus affording presence or absence of a secretion, which ample means for any solvent fluid to exert its was accomplished thus: Tying a narrow action on the roast-beef enclosed in the strip of litmus-paper round a small piece of quill. On examination of the ejected quills, recently caught fish, and fastening it to a I found no appreciable difference between thread, I gave it to an Anthea cereus who the contained meat, and similar pieces of greedily swallowed it; another thin slice of meat left in the water during the same the same fish was folded longitudinally over period; in one of them which had the meat a similar bit of litmus-paper, and given to a protruding somewhat from each end of the Crassicornis. If any acid secretion were quill, there was a maceration of the propresent, the paper would redden; if not, the truded ends, which looked like a digestive blue color would remain. On the following effect, but on submitting it to the micromorning the ejected morsels were examined, scope, I found the muscle-fibres not at all but not a trace of acid reäction was visible. disintegrated, the striae being as perfect as Repeating the experiment several times in any other part, and the maceration obviunder varying conditions, I came to the ously of a purely mechanical nature. A conclusion that no acid fluid was present in similar appearance is presented by meat, the digestive process of the Actinia. There after its ejection by the Actinia: it is pulpy, still remained a doubt. Solvent secretions colorless, but the muscles are not disinteare either acid or alkaline. It was necessary to make similar experiments with an alkaline reagent. This was done, and with similar results. It is worth noting that M. Hollard equally failed in detecting an acid or alkaline reäction, which is a confirmation of my experiments.

grated.

I dare not pause now to touch upon the many topics which are suggested by the conclusion to which these investigations led me. It will be enough just to note here the progressive complication of the digestive function in the progressive complexity of the animal series. Starting from the simple cell, which draws its nutriment from the plasma surrounding it, by a simple process of endosmosis, we first arrive at the mouthless Actinophrys or Amaba, which, folding its own substance over the food, presses out such nutriment as it can ; we then reach the Infusory with a mouth, but without stomach of any kind; † and the Polype, which has a portion of its integument folded in, serving both for mouth and stomach, but not anatomically differing from the external intigument, nor physiologically differing in its action from that of the Amaba's gelatinous substance; we then ascend to the † Nobody now believes in Ehrenberg's Polygastrica, or many-stomached animalcules.

The Actinia do not effect their preparation of nutriment by chemical means; and in our strict sense of the term, they cannot be said to digest. I was anxious to see how far mechanical means were employed, and for this, Reaumur's admirable experiment was a guide. In his day it was supposed that digestion was a purely mechanical operation, the food being ground into a pulp in the stomach. He took hollow silver balls, perforated with holes, and. filling them with meat, caused them to be swallowed by a dog. When they had remained a suitable period in the animal's stomach, they were withdrawn by the thread attached to them. If the digestive process were mechanical, the meat would be protected from all grinding action, by the silver covering; if chemical, Trembley turned a Hydra inside out, and the meat would be digested; and digested stomach. This has been held as proof that a found the outside perform the function of a (or rather chymified) it proved to be; show-muscus membrane is only a reflection of the skin, "Il est remarquable, et je m'en suis souvent But from what has been advanced in this paper. assuré, que les papiers réactifs plongés dans cet the reader may suspect that, inasmuch as the organe, et dans la cavité inférieure, soit au moment polype has no mucus membrane whatever, the sode la digestion, soit chez l'animal à jeûn, ne don-called stomach not being anatomically distinguishnent ancun indice d'acidité, ni d'alcalinité.""Etudes Zoologiques sur le genre Actinia." Revue et Magazin de Zoologie, No. 4. 1854.

able from the external skin, and the process of digestion being wholly mechanical, the current opinion is not proved by Trembley's experiment.

Annelids having a real intestine, lying free chres, are placed in the earth, and then in the general cavity, but only moderately, smile forth as golden wheat. What we call when at all, furnished with secretory appa- growth, is it not a perpetual absorption of ratus; and so on till at length we reach the Nature, the identification of the individual Mammalia, with their marvelously complex with the universal? And may we not in digestive apparatus. Corresponding with speculative moods consider Death as the this increasing complexity of the organs grand impatience of the soul to free itself is the increasing complexity of the food from the circle of individual activity,-the which the animals digest, from simple gases yearning of the creature to be united with up to meat. the Creator?

If all were not so marvellous in Nature, would not the marvellous fact that food at all exists arrest us? Food is what the organism can separate from the world around it, converting what it separates into its own life. May we not consider Life itself as an ever-increasing identification with Nature? The simple cell, from which the plant or animal arises, must draw light and heat from the sun, nutriment from the surrounding world, or else it will remain quiescent, not alive, although latent with life, as the grains in Egyptian tombs, which, after lying thousands of years quiescent in those sepul

As with life, so also with knowledge, which is intellectual life. In the early days of man's history, Nature and her marvellous ongoings were regarded with but a casual and careless eye, or else with the merest wonder. It was late before profound and and reverend study of her laws could wean men from impatient speculations; and now, what is our intellectual activity based on, except on the more thorough mental absorption of Nature? When that absorption is completed, the mystic drama will be sunny clear, and all Nature's process will be visible to man, as a divine effluence and life.

SHAKSPEARE'S PORTRAIT.-The following A new Plan for Street Railways.-By J. Notes relative to portraits of the great poet oc- W. Rammell, C. E. London: Edward Stanford, cur in one of Vertue's MSS. in the British Mu-1857.-This is a sketch of a plan for an atmos

"A Copy of the Picture of Shakespear, painted, and in posesion of the Lord Halifax, which picture Sr Godfrey painted for Dryden, and Dryden made a Poem on Sr Godfrey. In the possession of Mr. H. Howard, 1716.

"The Picture of Shakespear, one original in possession of Mr. Keych of the Temple [1719]. He bought it for forty guineas of Mr. Baterton, who bought it of Sr W. Davenant, to whom it was left by will of John Taylor, who had it of Shakespear. It was painted by one Taylor, a player, cotemporary with Shakespear and his intimate friend. Another of Shakespear, painted in oil, by, 1595.

"1719. Mr. Betterton told Mr. Keck several times that the Picture of Shakespear he had was painted by John Taylor, a Player, who acted for Shakespear. This John Taylor, in his will, left it to Sr Will. Davenant, and at the death of Sr. William Mr. Betterton bought it, and at his death Mr. Keck bought it, in whose possession it now is. These following verses, to put under the plate [?] of Shakespear, are made by Mr. Keck purposely at my request:

"Shakespear! such thoughts inimitable shine; Drest in thy words, thy fancy seems Divine, 'Tis Nature's Mirrour, where she views each grace,

And all the various Features of her Face." "

pheric railway to be raised 14 feet above the level of the London streets; only the framework of the rail would be erected and supported by strong cast iron rods, so as to exclude as little light and air as possible from the houses along the suggested line. It is proposed to make the railway constitute an endless course, like a race course, so that the trains would all circulate in the same directiou. A subterranean railway exists, we believe in Paris; but the expence of tunnelling for such an undertaking would be enormous. The atmospheric principle, though it failed miserably for long distances and high speeds, might very possibly prove, as the designer hopes, more applicable to such a scheme as this, where the distance would be short and the average speed very moderate. The greater quiet of an atmospheric line would render it particularly desirable for such a purpose.-Economist.

STRADA AND SHAKSPEARE-In reading Vorstius, De Latinitate merito suspectá, the other day, I came upon a passage (p. 18.) in which that author criticises Strada for using the phrase, integumento corporis se evolvere,' " instead of "mori." It seemed worth "making note of," from its identity in meaning with Hamlet's "shuffle off this mortal coil."-Notes and Queries.