August Carl Joseph Corda

“ In the Oscillatoriae, the Closteria and several other genera, I never was able to discover these feet.
The motion of the animalcules is seldom performed by the vesicular feet. The Frustuliae and Naviculae swim by a slow motion of the whole body; the Cosmaria and Euastra, by floating; the Diatomeae, by moving every one of their limbs; and the Oscillatoriae by a vermicular creeping, similar to the motion of earth-worms. ”

“ In the middle of that chaos of limy, often stinking and putrid substances, apparently deprived of life, the eye, powerfully armed, discovers ideal proportions and symmetrical forms, which the most fecond imagination of an arabesque painter could not create. ”

“ The propagation of the Oscillatoriae and Diatomeae is probably performed by decomposition of the parts; I never saw, however, propagation take place by division, admitted and even described by several naturalists, such as it may be seen in Infusoria of a higher category, and such as it has been admirably described by Mr. Ehrenberg. What has been hitherto called division of individuals was only animalcules, parts of a whole or of a chain of animals. I never saw new limbs growing upon one of the animalcules separated from the chain ”

“ In the Closterium costatum each horned extremity of the cuirass is truncated, and a larger, blunt and more opened mouth (fig. 61. 63. b. b.) comes out of its edges. Between this orifice and the content of the animalcule, through which the intestinal tube passes, the Closteria present a peculiar organ, which I name rotatory bladder, without knowing its functions. Some naturalists have taken those bladders for feet; but feet, entirely surrounded with a cuirass, and without any communication with the outside, would answer very ill the purpose of moving. ”

“ Water, a solid substance, heat, a beginning putrefaction, appear indispensable to the production and propagation of the animalcules; and such conditions are in fact always united. Without moisture, they never live; a solid substance must offer a basis to moisture, and, according to physical laws, the contact of the one with the other generates heat, and only by the simultaneous action of moisture and heat can putrefaction take place. ”

“ In the cuirassed animalcules (such as the various species of Surirella, Navicula, Closterium and Cosmarium) , the epidermis clothes the whole internal surface of the cuirass, and lines it like a bag.
In the Surirella Venus (Pl. I. fig. 4.) the epidermis possesses manifestly muscular strength, and when the muscular bag opens itself, it opens the cuirass, and by its contraction, it closes entirely the valves.
In the Cosmarium deltoïdes (fig. 19.) the two valves of the cuirass separate themselves by the muscular strength of both bladders (a.) ”

“ Some of these animalcules are always seen creeping in company under the microscope.
The Oscillatoria subulata (fig. 71—72) , standing upright, cannot creep with the whole body, but that remarkable creature seems to be constantly employed to its own propagation, considering that the coat of the mother opens itself again, as well as the still younger one (c. d. e.) . This last filament in the place where it abandons the opening of the coat, is articulated, as well as the coloured content of the maternal filament (d.) ”

“ The Cosmarium bipes (fig. 20) has a cuirass of the same form, and appears however always split on its external surface, the more so as, during fecondation, this fissure (fig. 20. a. a) opens itself. In the middle of the lines which unite the two cuirasses of an animalcule, we see a nearly quadrangular opening of the uniting points; which opening is the mouth. On both sides of it are two openings (fig. 20. b.) , through which the animalcule pushes a scarcely perceptible bladder, by means of which it sticks to the inside of the glass. I name therefore these openings pedal holes. ”

“ Does it meet larger bodies, it adheres to them or ascends over them, but it very soon puts aside the smaller ones, or, as the Naviculae do, drives them along with itself.
The Frustuliae move in less than a minute, upon a surface of one line. The Oscillatoriae, in four and twenty hours, move from one to four inches.
Our Diatomeae, found in rivers, are almost motionless; those which inhabit the sea move quicker. Many animalcules of this class move only during the night. ”

“ A flat bit of glass, as thin as paper, very pure and transparent, is placed over the animalcules, which are flattened by the pressure of the glass, so long as the observation lasts. The second, requiring still more dexterity, takes place by separating the larger species, with a very sharp and cutting needle, but it requires an extremely good eye and patience. ”

“ These myriads of beings are however animated, presenting, under the same type, an infinite variety of forms; these corpuscules, whose size is frequently the 0,000015, viz: the 15millionth part of a Paris inch, and seldom more than the 9thousandth part, are endowed with organs, simple indeed, if we compare them with animals of superior orders, but complicated, proportionally to their own body. ”

“ All the points and cuts are still obtuse and rounded; among the 52 points coming on each side of the body, 19 only are developed, which, divided later by new incisions, grow angulous, sharp and pointed. ”

“ Those which magnify only 5—600 times, are unfit for such researches. A particle of the green thermal substance, of the size of a pin’s head, is placed upon the object-glass, and torn between two sharp instruments, or, if wanting, with pins ”

“ I. fig. 13. c. c.) which, when the animalcule dies, is irregularly dissolved. The genus Scalptrum and some species of non-described Naviculae, ean expell, without dying, the coloured content, through the opening found on the surface of the belly (Pl. V. fig. 70. b.) and these animalcules seem to possess the faculty of reproducing the content.
This content is equally seen in the Diatomeae and Fragilariae, and the two extremities of the body alone, being empty, are transparent. ”