Spore

“ These spores are definite products. In the face of some experimental facts one was tempted to inquire: Have these spores any capacity to resist heat greater than the adults? It was not easy to determine this question. But we at length were enabled to isolate the germs of seven separate forms, and by means of delicate apparatus, and some twelve months of research, to place each spore sac in an apparatus so constructed that it could be raised to successive temperatures, and without any change of conditions examined on the stage of the microscope. ”

“ The fact that the protoplasm is denser and the spore capsule thicker (the percentage of water in each is decidedly less than in the growing cell) gives the spore the property of much greater resistance to all destructive agencies than the active bacterium has. For example, all actively growing cells are destroyed by boiling in a very few minutes, while some spores require several hours’ boiling. ”

“ A spore-wall is soon secreted and the sporangium has now resolved itself into a mass of spores, traversed by the strands of the capillitium and enclosed in a sporangium-wall, connected with the substratum by a stalk. As ripening proceeds, the wall becomes membranous and readily ruptures, and the dry spores may be carried abroad on the currents of air or washed out by rain. ”

“ Molds develop from spores which are always floating about in the air. When a spore falls upon a substance containing moisture and suitable food it sends out a fine thread, which branches and works its way over and into the attacked substance. In a short time spores are produced and the work of reproduction goes on. ”

“ Some are capable of moving from cell to cell in the body as do the white blood-corpuscles. They all agree in the production of spores—hence the name.
At certain stages in their development the nucleus within the body of the organism divides again and again until there are a great many daughter nuclei, each accompanied by a small mass of protoplasm, often inclosed in a little sac or cyst of its own. This is the process of spore-formation and we see that from a single individual we may have by division, not two animals as in the amœba, but a score or more of them. ”

“ Thus the growth of the germ-tubes arising from growing spores of fungi is directed by their chemotropism. When, for example, a spore falls upon a leaf on or in which the fungus can develop, it sprouts, and when the young germ-tubes reach the stomata (which see) , they turn in and ramify in the interior. ”

“ The single vascular bundle supplies a branch to the base of each sporangium. The latter arises from a number of superficial cells, the cells destined to form the spores being derived from a single one of these. A tapetal layer is derived from the cells surrounding the sporogenous group, and the arrest of a number of the spore-mother-cells further contributes to the nourishment of the remainder, each of which gives rise to four spores. ”

“ I have found it as you predicted a matter of considerable difficulty to find the mature forms of the Gemiasmas in the blood, but the spore forms of the vegetation I have no difficulty in finding. The spores have appeared to me to be larger than the spores of other vegetations that grow in the blood. They are not capable of complete identification unless they are cultivated to the full form. They are the so-called bacteria of the writers of the day. They can be compared with the spores of the vegetation found outside of the body in the swamps and bogs. ”

“ The resultant aftergrowth must necessarily be almost entirely composed of spore-bearing organisms. A small number of the most resistant members of non-sporulating organisms may also be present but they will, in the majority of instances, form a very small minority. ”

“ Resting Stage.—Spore Formation.—Conditions influencing spore formation: In an old culture nothing may be left but spores. It used to be supposed that spores were always formed, so that the species might not become extinct, when
(a) The supply of nutrient was exhausted. [Pg 138]
(b) The medium became toxic from the accumulation of metabolic products.
(c) The environment became unfavourable; e. g., change of temperature.
This is not altogether correct; e. g., the temperature at which spores are best formed is constant for each bacterium, but varies with different species ”

“ For this spore, though so small as to be visible only by microscopic aid, had a previous history, which may be traced without difficulty. It was generated with hundreds [Pg 118] more, in one of many capsules, which, were crowded together, beneath the oval bit of membrane, that covered one of the brown spots (sori) , which were developed in the under surface of the fronds of an earlier Lady-fern. That earlier individual had in turn passed through the same stages of sporal frond, prothallus, spore, theca, sorus, frond, prothallus, spore, theca, sorus, frond, prothallus, &c.—ad infinitum. ”

“ What are called white spores may be creamy, dirty, yellowish or brownish-white; pink spores will vary from almost white to reddish and salmon-color; brown spores from light-ochraceous through cinnamon to rusty; purple spores from dark-violet to purplish-black. Experience alone will enable the student to decide which color series is present. The Genera Charts, preceding the five different color series, show typical spore colors only. Again, authors describing the species frequently fail to see colors alike; if they do, their names for them frequently vary. ”

“ Near the habitations of animals and plants, where the spores are known to be in abundance, the development would be naturally at a maximum, and we should expect that the growth would diminish in proportion as the microscope indicated that the spores diminished in the atmosphere. ”

“ The spores, again, are microscopic, while the smallest of true seeds can be not only seen but easily picked up. You have, doubtless, met with the peculiar fungus called a puff-ball, and amused yourselves by watching the little clouds of impalpable dust which are shaken from it on the slightest motion. Those fine clouds, not nearly so visible as a film of candle smoke, are composed of innumerable spores, and such are the representatives of seeds in every member of the great section of the flowerless plants. ”

“ But if we look at the cloud of spores that can be shaken from a single spike of a club-moss, then imagine this to be repeated a thousand times from each branch of a fairly tall tree, and then finally picture a whole forest of such trees shedding in due season their copious showers of spores to earth, we shall perhaps be less amazed than we were at first thought, at the stupendous result wrought out by so minute an object. ”

“ By simply breathing upon them they suddenly fly open, and are endowed with motion, that is, if they contain spores. The spores on germination produce a green confervoid-like mass of threads, from which the young plant arises. ”

“ The existence of a parasite in this affection in the form of minute rods and its power of reproducing the disease are among the best-established facts in medicine. It is also known that these rods form seeds, or spores, as they are termed, in their interior, after the death of the patient, which germinate again in proper soil. These spores are the most durable and resisting objects known in animated nature. If kept in the state of spores they possess an absolute immortality ”

“ As the spores are forming, an abnormal growth is set up in the cells of the part attacked, which in consequence becomes enormously enlarged (Fig. 38, A) , single grains sometimes growing as large as a walnut. As the spores ripen, the affected parts, which are at first white, become a livid gray, due to the black spores shining through the overlying white tissues. Finally the masses of spores burst through the overlying cells, appearing like masses of soot, whence the popular name for the plant. ”

“ Nobody cares for planting the poor fungus: so she shakes down from the gills of one agaric countless spores, any one of which, being preserved, transmits new billions of spores to-morrow or next day. The new agaric of this hour has a chance which the old one had not. ”

“ Further, it has been proved that there is sometimes more or less of a metamorphosis in the life history of certain species of bacteria. The same species may form a short rod, or a long thread, or break up into spherical spores, and thus either a short rod, or a thread, or a spherical form may belong to the same species. Other species may be motile at one time and stationary at another, while at a third period it is a simple mass of spherical spores. ”

“ When mature, the knobs burst open, and the fine spores are scattered in the air. The various parts of the mould are best seen in position by scattering some of the spores, or a little dust from a shelf, upon the surface of clear, colourless fruit-juice in a glass vessel, and following the stages of growth with a lens. It then becomes clear that the mould—like the mushroom—consists of (a) a buried tangle or mycelium of hyphal threads which take in the plant’s food, and of (b) an aërial part which scatters the spores. ”

“ In the budding method of multiplication a large number of buds are formed, either on the surface or in the interior of the organism. Where divisions or buddings follow one another rapidly, without the segments separating immediately after their production, numerous forms develop, which are often unlike the parental forms, and these are termed swarm spores or spores. ”

“ Usually each species occurs upon a distinct species of plant, as is the case with parasites generally. In many of them the spots (sori) exhibit a thin membrane covering the spores, which bursts down the middle, so as to bear some resemblance to a capsule. But there is no true capsule, the membrane consisting of the epidermis of the leaf or stalk of the plant, which is raised and{103} torn by the expansion of the growing fungus; so that the peridium is spurious, as belonging to the matrix, and not to the fungus. ”

“ We come now to consider the structure in the Sporidiifera, in which the fructifying corpuscles or germs, whether called spores or sporidia, are generated within certain privileged cysts, usually in definite numbers. In systematic works, these are included under two orders, the Physomycetes and the Ascomycetes. ”

“ I have drawn from Nature, in the six respective cases, the condition presented by each organism at the time of emitting its spores. Fig. 1 is the genetic product of an oval monad, with a pair of flagella; it rapidly increased by fission; then in a remarkable manner a pair blended, became one in the form of a sac, the sac burst and poured out, as the drawing portrays, innumerable spores, which were watched continuously until they were seen to develop into the parent condition. Fig. 2 gives a similar product of another form ”

“ Some genera shed their spores sooner and more freely than others. A surplus of spores is objectionable. In order to know when a print is plainly made, without disturbing the process, have either a specimen of the same age, or a piece of the one under the bowl, on another piece of gummed paper, covered in like manner. ”

“ Dematie ́i.—In this family the filaments upon which the spores are placed are not compacted as in Tubercularia, but separate; and they are of a dark brown or black colour.
Sporoc ́ybe alternáta (Pl. VII. fig. 18) is occasionally found upon decaying vegetable substances, forming little black velvety spots or patches. The mycelial filaments are exceedingly minute, septate, tapering at the ends, and terminated by a little tuft of pear-shaped cells, from which the black simple spores arise singly. ”

“ Here the contents of certain cells break up endogenously into a great number of spores, which are distributed as a fine dust. Resting spores are also known. In these cases, certain cells of a colony of unicellular plants or of the filaments of multicellular plants enlarge greatly and thicken their wall. When unfavourable external conditions supervene and the ordinary cells become atrophied, these cells persist and reproduce the plant with the return of more favourable conditions. ”

“ From his or her body are continually given off in all directions, by the skin, the breath, the perspiration and the other secretions, millions of spores so minute that 20,000 placed end to end would not measure 1 inch in length, and a group of them the size of a grain of sand might contain 50,000,000. ”

“ The ejection of the spores by mechanical means takes place in a number of Ascomycetes, and should many spores be simultaneously ejected, a dust-cloud may be seen with the naked eye to arise in the air from the fruit-body. ”

“ The young spores that came into view in this were watched through to the adult condition. Bearing on the subject of spontaneous generation, this fact was learned, that, while a temperature of 140° Fahr. was sufficient to cause the death of adults, the spores were able to grow even after having been heated to 300° Fahr. ”

“ Under the microscope you clearly perceive that these insects have organs, orifices, excrement; they do, most emphatically, copulate. Escorted on the one side by the Bos or Warble, on the other by the Hessian Fly, Miss Ormerod advanced statelily, if slowly, into the open. Never did her features show more sublime than when lit up by the candour of her avowal. “This is excrement; these, though Ritzema Bos is positive to the contrary, are the generative organs of the male. I’ve proved it.” ”