FROM SIMPLE PERCEPTIBLE MATTER. 563 
plainly in their interior, either a developed simple intestinal canal, or 
clearly defined, vesicular, coloured pouches similar to stomachs. In 
those animalcules which had fully charged themselves, I could also as 
plainly perceive in other parts of the body, particularly the hinder 
parts, secretions of the superfluous matters through a separate anal 
aperture. These traces of organization in the most minute beings were 
now no longer useless indications of organs, but evidently real organs 
performing their functions—cilia, mouth, intestine, anal aperture. This 
result, long sought for indeed, and as it were extorted, to a degree of 
clearness beyond expectation, urged me immediately and eagerly to 
employ the same means for the investigation of all the species of infu- 
soria found in my neighbourhood, which I had before observed in 
various ways, and of which I possessed drawings, in order to elucidate 
their organs of nutrition, and to delineate and determine their form; 
whilst at the same time it was evident that the knowledge of their 
organization was by no means completed by the discovery of the organs 
already mentioned. The eggs, muscles, and eyes of the wheel-animal- 
cules rendered probable the existence of similar systems in the others 
also; and hence I not only most carefully reviewed in every manner 
all the species occurring near Berlin, as to organs of nutrition, but I 
also endeavoured to throw more light on the whole organization of 
these minute beings; thus I ascertained with much greater certainty 
the true relation of the free muscles of movement, the whole course of 
the intestine, the course and form of the female and male generative 
organs, the great frequency of the beautiful red eye-points, regular 
branching traces of vessels, and besides, little glandular bodies and 
fibres in the interior, which are not at all opposed to the character of 
nerves. In the throat I distinguished teeth so evident, that these alone, 
had they been sooner discovered, would have sufficed to render cre- 
dible the perfection of the rest of the organization, according to the 
type of larger animals. In the smallest infusoria, which up to that time 
had always: been considered as homogeneous globules, I recognised not 
only an apparent internal belly, and at times an apparent intestinal 
anal, with mouth and anal aperture, but also, at least in one genus 
(Euglena), red points similar to eyes. 
Of great importance however was, amongst other acquisitions, the 
light thrown on their organs of reproduction. I perceived a very fine 
granular reticulate matter, filling the intervening spaces of the intes- 
tinal canal, to be secreted through the anal aperture, which charac- 
terized itself plainly as a laying of eggs: the animalcules became at the 
same time smaller, plicated, and edged, sometimes changed their form 
very remarkably, but still actively continued to swim. Of a similar 
character appeared to be the old observation, often repeated by me, of 
a spontaneous partial solution of the smaller infusoria into fine granules, 
Vor. I—Parrt IV. 2Q 
