338 Reviews. [April, V.?On Protoplasm.1 No one can, -we tliink, mistake the tendency of modern biology; whenever it is possible, and sometimes when it is hardly possible as yet, rule and measure are called in to give exactness of expression to our knowledge of the subject, and exact data are formulated in terms of mathematical precision. Improved chemical processes are gradually enabling us to resolve those " waste heaps or dust bins labelled extractive matters" into their components; and many phenomena which, not under- standing, we used to term vital, have been found after all to be readily intelligible on the ordinary principles of chemistry or physics. So many things heretofore supposed to depend directly on the vital principle have been thus resolved that some have gone so far as to call in question the existence of any force different from the physical forces we sec at work around us. Undoubtedly the discovery of the correlation of these forces, the fact that one is transmutable into another without diminution and without increase, has had a most important bearing on physiological doctrines. If in the physical world we see motion transformed into heat, this into light and chemical action, chemical force into electricity and magnetism, and so on, we are tempted to make another step in advance. In vegetable life we know that light and heat are the forces whereby carbon is fixed and oxygen set free, whereby ammonia is converted into com- plex organic compounds, and an infinite variety of other changes is effected. In animals it has been found that digestion is a chemical process, absorption to a great extent a physical one; respiration is partly physical, partly chemical; not a muscular movement can be performed without the consumption of fuel in some shape or other; in short, in all these so called vital acts the physical forces are equally manifest as if there were no com- plex organic medium through which to exert their influence. The question therefore arises, Suppose we take the simplest " i 1. The Fortnightly Review (February 1st, 1869). On the Physical Basis of Life. By Professor Huxley. London. 2. Protoplasm or Life, Force and Matter. By Lionel S. Beale, M.B., F.R.S., Fellow of the Royal College of Physicians, Physician to King's College Hospital. Second Edition. London. in relation to on 3. -As regards Protoplasm Professor Huxley's' Fssay the James Physical Basis of Life. By Hutchison Stieling, F.U.C.S., LL.D. Edin. Edinburgh. Gilbert W. 4. on Physiological Subjects. By Child, M.A., F.L.S., &c., Essays London. Lecturer on Botany at St. George's Hospital. and Present the Use in 5. The Cell Doctrine, its History State, for of Students Medicine and Dentistry. By James Tyson, M.D., Lecturcr on Microscopy in the University of Pennsylvania, &c. Philadelphia. 1872.] On Protoplasm. 339 organism known, and consider well its functions, is there any- thing in these not explicable by physical force; shall we be forccd to call in some mysterious entity of which we know nothing, to explain the terms of its being? If we let fall a drop of white of egg yet unboiled, into water, this drop retaining its individuality and mixing not with the water, represents the simplest organised, or rather we might say unorganised, being. Haeckel calls it monerci, but herein consists the difference: this monera having 110 other structure than a drop of albumen, can move from place to place of its own accord, can change its shape in a thousand ways, can take in and make part and parcel of itself other and larger portions of albuminous matter, and can reproduce itself by throwing off a portion of its own substance, and all this it does by virtue of something we call life. But it has been roundly asserted that this property is in- in kind of matter we are now herent the with which dealing ; ?where it exists life exists, and where it does not exist no life is, insomuch that it has been called the physical basis of life ; let us call it protoplasm. The questions in dispute seem to formulate themselves thus :? Does the existence of protoplasm, using the word in a strict sense, imply life; may life and matter co-cxist whilst the latter assumes 110 distinctive form ; can life begin da novo and without the agency of pre-existing life ? But to the preliminary inquiry of what is protoplasm ? using the word-in the strict sense, we obtain 110 adequate reply. We are told that all forms of it contain carbon, hydrogen, nitrogen, and oxygen in certain proportions, but what these are we know not. Protoplasm, in a strict sense, is not known chemi- cally. If we seek for an example of protoplasm, we are referred to the well-known experiment with frog's blood. A drop is drawn from a blood-vessel of the animal and deposited 011 a piece of thin glass; this is placed under the microscope,and kept at a tem- perature of about 100? F., when by-and-by the white corpuscles will be seen to approach the edge of the blood drop, exhibiting distinct movements of the kind called amoeboid. Similar bodies are found in connective tissues, some wandering, some fixed, but apparently otherwise identical. To these we are referred as samples of protoplasm, but we are ignorant as ever of its chemical even indeed, this would seem to be far from simple composition; would in in fact the type of bodies leucocytes; protoplasmic of fat appear to have at all times during life a certain proportion combined with its albuminous matter, the sepaiation intimately of the death of these two constituents being the first certain sign forms of of the body. Professor Huxley tells us that all the pro- 340 Reviews. [April, toplasm yet examined behave similarly towards several reagents ; if this be true of protoplasm, it is certainly not true of the type of such bodies, albumen itself; for this sometimes will coagulate with acid, and sometimes will not; sometimes too it will coagu- late with heat, and sometimes it will not. Syntonin, globulin, and peptone are all varieties of albumen ; of all may different characters be predicated, but of none can it be said that it is the matter of life or protoplasm. Nay, if we fall back on what we are told is the type of protoplasmic struc- ture, a white blood-corpuscle or an amoeba, we find in its body certain portions apparently constituted differently from the rest, inasmuch as by a reagent such as acetic acid we can demonstrate the existence of particles called nuclei, which behave differently from the rest of the structure. The same is the case if the body be killed by an electric shock, without any chemical reaction. It is, however, perfectly true that in monera there is no nucleus, which shows that this is not quite essential to the performance of all the acts of life, but it is also quite true that in those bodies possessing a nucleus, changes in it generally precede changes in the mass of the being itself. If possible, this nucleus shows a more vigorous vitality; is it protoplasm ? If so, it reacts differently from the rest of the mass. If, therefore, we mean by protoplasm merely the simplest form of living matter, that is, if we make vitality the test of its existence, we can understand the meaning of the word. But it is plain that protoplasm is not a simple substance in all instances chemically identical; in this sense it is a varying admixture of more than one body of albuminoid constitution, reacting differ- ently with different reagents. Its presence is not the test of life, but life of its presence. Professor Huxley himself hints at these differences of properties when he speaks of the difficult digestibility of lobster protoplasms as compared with that of sheep; in other words, these two do not behave exactly in the same way towards the reagent we call gastric juice. There is, however, one sense in which we may make use of the word protoplasm with advantage; to illustrate this we must fall back on matters of history. When Schlciden had shown that the plant was built up of a scries of elements, as a house is of bricks, he investigated the structure of these elements, and found that in every instance they seemed to possess a cellular wall, slimy contents, and a nucleus, besides other things, as starch, chlorophyll, and such like. Schwann adapted these principles to the human body, and applied the term cell, in- troduced by Schleiden, to designate these ultimate vegetable elements, to designate also those of the human frame. Further- more, a similar constitution was predicated of them; that they 1872.] On Protoplasm. 341 consisted of cell walls, slimy contents, and nucleus; in short, that they were in every way analogous to the vegetable cells. But in 1835 Dujardin, then concerned in his inquiries into the Hhizopoda, discovered that they consisted of a substance irritable and contractile, having nothing of a cellular character; it was called sarcode. llesearches went on, and new discoveries were that made, especially the slimy substance of many animal cells was also contractile, until at last Max Schultze was able to show the that contents of animal cells were analogous to sarcode, and that the cell Avails were of comparatively little consequence compared with their contents. In the days when this universal character was predicated of all animal structures, blood cor- puscles, red and white, were a standing difficulty; by no means could the red globules be reduced to the highest or nucleated ccll type, and by many they were held to be free nuclei.