sarcophytes in the exudation from inflamed vessels, I was in doubt how they could pass through the coats of the vessels, in which no pores had ever been discovered; but I suggested that small granules or nuclei might so pass, and then grow into larger. But Dr. W. Addison had, in 1843, described the actual fact of emigration, by the sarcophyte first passing into the substance of the wall of the blood-vessel, and then being thrown out of it. To Dr. Addison, therefore, belongs the merit of having first discovered the emigration process. It was again accurately observed in the tongue of the frog, and described with perfect clearness by my lamented friend Dr. Augustus Waller. Although this demonstration of the exudation origin of lymph and pus cells did not attract notice at the time, yet many others besides myself adopted the exudation theory-that is, that of the origin of the chief products of inflammation, cellular as well as fibrous and fluid, in exudation from the inflamed vessels. This does

1 Philosoph. Magazine, 1846, p. 347. Dr. Norris has endeavoured to refer the passage of sarcophytes through the walls of vessels to a general fact, which he has beautifully illustrated by experiments, that colloid bodies can pass through each other's substance without breach of continuity. But these experiments were made with soap or glycerine bubbles, formed by a colloid of very different consistence from that of the walls of blood-vessels, even granting that these do consist of colloid protoplasm without endothelium, which is more than is admitted by the latest authors. (See Eberth, On the Minute Anatomy of the Capillaries,' in Stricker's Histology, p. 282.) It must be borne in mind that the walls of the capillaries continually resist the considerable pressure from the heart and arteries, which a soft colloid could not do. The walls must either consist of a very tough colloid, or be strengthened with endothelium scales. Observations render the latter alternative most probable, and it is conceivable that there may be minute interstices between these scales, containing protoplasm permeable to the active sarcophytes, but not pervious to the mass of the blood. The sarcophytes, when young, consist simply of soft colloid, which subdivides and passes through the interstitial protoplasm, and reunites into their original form outside the vessel, just as, in Dr. Norris's experiments, the bubble and the film regain their continuity after passing through each other's substance.

EXUDATION AND CELL-FORMATION THEORIES.

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not exclude a full admission on my part that the cell-life of the tissue is also brought into fuller activity; and that some inflammatory products arise from that source, as, for example, connective tissue cells, epithelium and epidermis cells, and others, which are produced in abundance in inflammation of particular tissues; but I hold that the more distinctive products of the inflammatory process, lymph, pus, and tubercle, and albuminous and fibrinous. matters in other varieties of form, are truly exudations from the inflamed blood-vessels; and I was enabled to trace most of the products to the chemical and physiological properties known to be in operation. It was in concordance with this view that I was led to class the products of inflammation as deposits. Similar views were subsequently brought forward by Rokitansky and other authors, and were generally adopted in this country, until within the last ten or twelve years, when they have been, in great measure, superseded by the cell-growth theory of the North-German school.

When Schwann and J. Müller propounded the general axiom that animal, like vegetable tissues, are formed by their elementary cells, they did not exclude the bloodvessels of the animal body from their share in the work by causing variations in the distribution of the nutritious fluid; but neither they nor most of their numerous followers, in advocating the cell-formation theory, seem to have sufficiently considered that the nutritious fluid itself abounds in the elements of cell-life. Consequently, the main fountain of cell-life was comparatively neglected, and all microscopes were turned on the tissues and their proliferating and formative elements. There, in these elements, was sought the origin, not only of the tissues. themselves, but of morbid products also; and pus, lymph, tubercle, cancer, &c. were all referred by Virchow to modifications of the proliferating power of the elementary

cells of connective tissue, and grouped together, in spite of their total dissimilarities in structure and history, under the general term of growths.'

6

But extended observation has already done much to rectify such hasty and partial generalisation. The very axiom omnis cellula e cellulâ' was upset by the discovery that there is no absolute need of a cell at all in a protoplasm or parent organism. Max Schultze1 says that the embryonal cells (so called), in which the unlimited power of tissue formation is most distinctly evident, consist only of a little mass of protoplasm and a nucleus.' A cell without a wall! But further, even the nucleus is not essential. Max Schultze has discovered a non-nucleated Amoeba (Amoeba porrecta) in the Adriatic; Haskel, a larger non-nucleated Protista, propagating by division, in the Mediterranean;2 and Professor Stricker mentions other instances, proving that the ideal type of a cell is a little mass of sarcode or protoplasm, without either cell wall or nucleus. This being the case, that the essential element of the protoplasm is independent of both cell and nucleus, it is surely a misnomer to use the word cell, and it is erroneous to suppose that all living matter must originate in either cells or nuclei. It appears, therefore, that Dr. Lionel Beale is more accurate in giving to all active protoplasm the term germinal matter or bioplasm, whilst cells and all other formed rudiments of tissue are expressed by the antithetical term formed matter; and both his language and his descriptions seem to answer well in their application to the products of disease.

In their indefatigable researches in the field of nature, if the German physiologists have not wholly emancipated their language from the trammels of the hypothesis of cytology, or cell-doctrine, they have greatly extended our 1 Stricker's Histology, vol. i. p. 7. 2 Stricker, loc. cit.

PROPERTIES OF BIOPLASM AND SARCOPHYTES.

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knowledge of the properties of elementary living matter; and inasmuch as the pale blood- or lymph-corpuscles are samples of this elementary matter or protoplasm, we are interested in these properties in connection with our present subject.

Although a bioplasm or perfect protoplasm may exist without any structure discernible under the highest microscopic powers hitherto applied, yet its vitality is abundantly manifest by its spontaneous motions, external and internal by its nutrition and growth, and by its power of reproduction. Its motions are displayed in its singular changes of shape; hence the term amoeba (ausißw, I change'). These changes give the amoebal mass a power of irregular locomotion, if floating in liquid; and some species also throw out processes like arms, with which they embrace other objects, and draw nourishment from them. In doing this the bioplasm seems to exert sometimes a solvent power on the matters seized; at others, one of absorbing them into its substance: in the case of colouring matter, its particles can be seen in the interior of the protoplasm, and by their motions show the intrinsic movements which are taking place.

Without dwelling longer on this curious and interesting topic, we have to recur to the white corpuscles, or sarcophytes, which as before said, are of the nature of protoplasm, and under circumstances of excitement exhibit these motions and properties of amoeboid matter. In the fresh-drawn blood of the frog, they have been seen to exhibit lively changes of form and locomotive movements, and to take into their interior milk globules and particles of colouring matter. As exudation globules, they show the wonderful power of emigration before mentioned; and when extravasated, their moving and solvent powers continue, and may aid in explaining some of the obscure changes in the tissues in inflammation and

suppuration.

For example, the disappearance of red blood corpuscles, and of the structure of tissues under the rapid increase of pus cells, which used to drive us to the assumption of a marvellous activity of absorption, now appears as a proof of the amoeboid voracity and digestive power of this active germinal matter.

And if the bioplasm exhibits this potent activity in the case of rich blood and acute inflammation, are we not to expect varied results, and less lively actions, when the blood is depraved, and the inflammation more chronic? This is a subject well worthy of direct investigation from this stand-point. Max Schultze observed the amoeboid cells of freshly drawn human blood increase in activity when the temperature was raised to between 95° and 104° F., but above that heat the movements cease, and the cells harden.1

How full of suggestion is this single observation! These little germinal elements are full of life and activity within a certain range of temperature; below it their activity diminishes; above it, it ceases, and they harden. This range of temperature, thus quelling amoeboid life and activity, is quite within that which occurs in inflammatory and febrile diseases; and how does the observation correspond with our clinical knowledge of the grave import of continued high temperature in pneumonia, bronchitis, or even febrile catarrh! It matters not what may be the cause of the rise of temperature to 104° and upwards in these cases. If the above observation is correct, such a heat injures the vitality of the plastic materials within and without the blood-vessels, and instead of their undergoing changes, by which they are either properly organised, or are eliminated from the tissues by transformation into pus globules, or other liquid discharge, they concrete into little solids, it may be still with the proliferating

1 Stricker's Histology, vol. i. p. 414.