Diabase

“ Chlorite also is abundant both in sheared and unsheared diabases, and with it calcite may make its appearance, or the lime set free from the augite may combine with the titanium of the iron oxide and with silica to form incrustations or borders of sphene around the original crystals of ilmenite. Epidote is another secondary lime-bearing mineral which results from the decomposition of the soda lime felspars and the pyroxenes. Many diabases, especially those of the teschenite sub-group, are filled with zeolites.
Diabases are exceedingly abundant among the older rocks of all parts of the globe. ”

“ When a little fresh blood is placed under the microscope, it is seen to consist of a colourless fluid filled with numerous little bodies, commonly called “blood-globules,” varying very greatly in size and shape, according to the animal from which they were taken. Those of the reptiles are very large, as may be seen at Fig. 4, Plate X., which represents a blood corpuscle of the Proteus. In this curious reptile the globules are so large that they may be distinguished during its life by means of a common pocket lens. ”

“ As I have explained, the tissues and organs of the higher animals break up under the microscope into a most ingeniously constructed network of tiny living gelatinous corpuscles with a nucleus in the centre—the cells. But our radiolarian has no more got tissues composed of cells than it has stomach or lungs or any other organ. It is merely a single cell with a nucleus and a jelly-like body. Yet in this case the single cell is a whole individual, a complete animal, that lives, moves, eats, breathes, and so on. ”

“ The amount of bile pigment eliminated during the day indicates that the destruction must be considerable, and since the number of corpuscles does not vary there must be an equivalent formation of new ones. This takes place in the red bone-marrow, where special cells are provided for their continuous production. In embryonic life their formation is effected in another way. Certain mesodermic cells, resembling those of the connective tissue, collect masses of haemoglobin, and from these elaborate red blood corpuscles which thus come to lie in the fluid part of the cell. ”

“ The matter which forms the mass of a cell is called protoplasm, or bioplasm. It resembles somewhat the white of a raw egg, which is almost pure albumen. Cells make up the body, and do its work. Some are employed to construct the skeleton, others are used to form the organs which move the body; liver-cells secrete bile, and the cells in the kidneys separate poisonous matters from the blood in order that they may be expelled from the system. ”

“ The whole of the alimentary wall is formed of a single layer of hypoblast cells.
A most important organ connected with the alimentary system still remains to be dealt with, viz. the atrial or peribranchial cavity. The first rudiments of it appear at about the time of hatching, in the form of a pair of dorsal epiblastic involutions (fig. 8 V. kl) , at the level of the junction between the brain and the spinal cord. These involutions grow inwards, and meet corresponding outgrowths of the branchial sack, with which they fuse. ”

“ Bile cells which, while performing their functions, grow and give origin to new bile-cells, are, when they decay and disappear, replaced by these: the cells descending from them do not migrate to the kidneys, or the muscles, or the nervous centers, to join in the performance of their duties. And, evidently, unless the specialized units each organ is made of gave origin to units similarly specialized, which remained in the same place, there could be none of those settled relations among parts which characterize the organism and fit it for its particular mode of life. ”

“ Regular differences exist between men and women; the latter have, with the same amount of hæmoglobin, a specific gravity lower by 2 to 2.5.
Should the parallelism between the number of red blood corpuscles and the amount of hæmoglobin be considerably disturbed, the influence of the stroma of the red discs on the specific gravity of the blood will then be recognisable. Diabella calculates, that with the same amount of hæmoglobin in two blood testings, the stroma may effect differences of 3-5 per thousand in the specific gravity. ”

“ As the blood-tubes are not only supply-pipes but sewers and drainage canals as well, it is a good thing to have some kind of tiny animals living and moving about in them, which can act as scavengers and eat up some of the waste and scraps; and hence your microscope will show you another kind of little blood corpuscle, known, from the fact that it is not colored, as the white corpuscle. These corpuscles are little cells of the body, which in shape and behavior are almost exactly like an ameba—a tiny "bug," seen only under the microscope, that lives in ditch-water. ”

“ It is not very improbable that the kidney of the frog shares, or performs, some of the functions of the rabbit's liver, or parallel duties, in addition to the simply excretory function. Since specialization of cells must be mainly the relatively excessive exaggeration of some one of the general properties of the undifferentiated cell, it is not a difficult thing to imagine a gradual transition, as we move from one organism to another, of the functions of glands and other cellular organs. ”

“ In all the epithelial tissues that we have considered we have one feature in common: they are cells, each equivalent to the amoeba, that have taken on special duties-- in a word, they are specialists. The amoeba is Jack of all trades and a free lance; the protective epidermal cell, the current-making ciliated cell, the bile or urea-making secretory cell, is master of one trade, and a soldier in a vast and wonderfully organized host. We will now consider our second kind of cell in this organization, the cell of which the especial aim is the building round it of a tissue. ”

“ The inner layer, together with the fibres from the crura cerebri, gives rise to the major part of the white matter of the hemispheres and to the epithelium lining the lateral ventricles.
The outer layer of rounded cells becomes divided into (1) a superficial part with comparatively few cells, which, together with its coating of white matter, forms the cortical part of the grey matter, and (2) a deeper layer with numerous cells which forms the main mass of the grey matter of the hemispheres. ”

“ As the cell-wall grows thicker, fluids and gases penetrate its invisible pores with more difficulty; and with continuous increase of thickness the living protoplasmic bodies inhabiting its interior must finally die for want of food. They in effect build their own coffin, immure themselves living in their own cell-prison. But a wonderful provision prevents the food being entirely cut off. While the cell-wall is arching itself up more closely and thickly, a few doors and windows are still left open in it, through which communication may still take place with the adjoining cells ”

“ These two layers are the primary germinal layers. A third layer is subsequently formed between them, by the agency of one or both of them, and is called the mesoblast. From these three simple membranes, which are composed exclusively of cells, are formed all the complex tissues and organs of the adult man. The epiblast develops into the nervous system (brain, spinal cord, and nerves) , and the cuticle, hair, etc. The hypoblast develops into the cellular parts of the digestive canal, the liver, lungs, etc. The mesoblast develops into the muscles, bones, ligaments, blood-vessels, etc. ”

“ The sharply defined nucleus lies generally in the centre, comprises the greater part of the cell, and is above all distinguished by its intense colour with nuclear stains, which exceeds that of the nuclei of the leucocytes, and indeed of all known nuclei. This property is so characteristic that the free nuclei, which occur occasionally in anæmias, and particularly often in leukæmia, may be recognised as nuclei of normoblasts, although surrounded by traces only of hæmoglobin, or by none at all.
2. The megaloblasts. These are 2-4 times as large as normal red blood corpuscles. ”

“ I have removed some of the phosphate of lime from the brain-cavity, and although it has not been excavated to the cerebellum, the great depth of the brain is well seen, and the convex character of the cerebral lobes, between which a crest of bone descends mesially as in the ethmo-sphenoid mass next described. At each of the lower outer angles of the brain, extending into the cancellous brain-walls to the outermost film, is an ovoid convexity, covered with a thin film of bone. ”

“ The Lymphocytes. These are small cells, as a rule approximating in size to the red blood corpuscles. Their body is occupied by a large round homogeneously stained nucleus centrally situated, whilst the protoplasm surrounds the nucleus as a concentric border. Between nucleus and protoplasm there is often found a narrow areola, which doubtless results from artificial retraction. Nucleus and protoplasm are basophil, nevertheless in many methods of staining the protoplasm possesses a much stronger affinity for the basic stain than does the nucleus. ”

“ Such a cell-plate is called a medullary ray. It is essentially a living tissue, and serves to place all the living cells of the secondary vascular tissues in communication. It conducts plastic substances inwards from the cortex, and its cells are frequently full of starch, which they store in winter. They are accompanied by intercellular channels serving for the conduction of oxygen to, and carbon dioxide from, the living cells in the interior of the wood, which would otherwise be cut off from the means of respiration. ”

“ The perfecting of the microscope led to a full comprehension of the great doctrine of cell-structure and the establishment of the facts— (1) that all organisms are either single corpuscles (so-called cells) of living material (microscopic animalcules, &c.) or are built up of an immense number of such units; (2) that all organisms begin their individual existence as a single unit or corpuscle of living substance, which multiplies by binary fission, the products growing in size and multiplying similarly by binary fission ”

“ Cells have different powers of selecting and secreting diverse materials from the blood. Thus, some secrete bile to202 carry to the liver, others secrete saliva for the mouth, others take up the tears, and still others take material for the brain, muscles, and all other organs. Cells also have a converting power—of taking one kind of matter from the blood, and changing it to another kind. They are minute chemical laboratories all over the body, changing materials of one kind to another form in which they can be made useful. ”

“ The sides of these globules are studded with amoeba-like organisms, each having a cilium, or appendage resembling an eyelash, which is constantly vibrating, and so establishing a current in a direction downward into canals which open into great, funnel-like, or crater-like orifices. These great orifices are the exhalant apertures, the pores inhalant apertures. The food and oxygen in the stream of water is appropriated by the sponge-organisms individually as it flows by.
When placed under the microscope, the living sponge is a wonderful sight. ”

“ On blood corpuscles, see ‘Quarterly Journal of Microscopical Science,’ April 1874, p. 185.’ [page 61]
under a high power, is the appearance of the finest granules in the fluid within the cells, making it slightly cloudy. These granules soon aggregate into small globular masses. I have seen a cloud of this kind appear in 10 s. after a drop of a solution of carbonate of ammonia had been given to a gland. With dark red leaves the first visible change often is the conversion of the outer layer of the fluid within the cells into bag-like masses. ”

“ The two-walled hemisphere soon grows into a nearly closed sphere, with a central cavity into which projects a vascular tuft. For this tuft the thickened inner wall of cells forms a lining, and at the same time the outer wall becomes thinner, and formed of flattened cells, except in the interval between the openings of the segmental tube and kidney tubulus, where its cells remain columnar. ”

“ Each cell contains a darkly-stained nucleus (Nu) , but the nuclei are seen only where they lie in the plane of the section. The protoplasmic area about the nucleus in each cell appears to be occupied mostly with hollow cavities of various sizes (a) , but in life each cavity contains a small globule of fatty oil. The proto- plasmic material between the oil globules contains also glycogen, or animal starch, as can be shown by staining with iodine. ”

“ So Nature shapes her hyaline vesicles and modifies them to serve the needs of the part where they are found. The artisan whirls his rod, and his glass bubble becomes a flattened disk, with its bull's-eye for a nucleus. These lips of ours are all glazed with microscopic tiles formed of flattened cells, each one of them with its nucleus still as plain and relatively as prominent, to the eye of the microscopist, as the bull's-eye in the old-fashioned windowpane. Everywhere we find cells, modified or unchanged. ”

“ The next changes to be noticed take place in the nuclei which were not converted into blood-corpuscles, but which were to be seen in the protoplasm surrounding the corpuscles. They become more numerous and smaller, and, uniting with the protoplasm in which they were imbedded, become converted into flat cells (spindle-shaped in section) , and in a short time form an entire investment for the masses of blood-corpuscles. The same change also occurs in the protoplasmic processes which connect the masses of corpuscles. ”