FROM SIMPLE PERCEPTIELK 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 tiirough 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 alwajs been considered as homogeneous globules, I recognised not 

 only an apparent internal belly, and at times an apparent intestinal 

 canal, with mouth and anal aperture, but also, at least in one genus 

 (Eufflena), 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, 



Vol. I.— Part IV. 2 y 



