566 EHRENBEUG ON THE ORIGIN OF ORGANIC MATTER 



13. The results of my observations call to mind the old physiolo- 

 gical proverb, Omne vivum ex ovo. In my observations pursued 

 with so much zeal for twelve years, I never witnessed the spontaneous 

 origin of one infusorium from slime or vegetable tissue ; but have often 

 enough seen the laying of eggs, and the young come out of the 

 larger eggs. Supported by such experience, I am of opinion that these 

 animals are never formed by generatio primitiva, but originate from 

 eggs. Whether then the eggs dispersed about are only in part the 

 product of laying, or in part the product of a generatio primitiva, is a 

 question which is not quite ripe for determination*. 



14. The active motions and contractions in plants and their parts, 

 especially in Algce, ought not to give rise to the supposition of an 

 animal nature, even when they are called infusorial or animal motions. 

 Internal nutritive organs, and a definite oral aperture for the reception 

 of solid substances, which may be demonstrated, distinguish the appa- 

 rently most simple animal from plants. I have never seen in my 

 numerous experiments the motive algae seeds take up the smallest 

 quantity of solid nutriment ; and thvis the fruit-strewing alga may be 

 distinguished from the monads which swarm round it in the same 

 manner as the tree from the bird. 



15. Finally, I call attention to this fact, that experience displays an 

 unfathomableness of organic creations referred to the smallest portion 

 of space, in like manner as the heavenly bodies are to the largest portion, 

 the preternatural limits of both requiring optical assistance. Hypo- 

 theses may be started even so far as to the existence of primitive 

 substances ; it cannot yet be brought before our experience. The 

 milky way of the smallest organization passes through the genera 

 Manas, Vibrio, Bacterium, and Bodo. 



In a more recent memoir read in 1831, which will appear in a few 

 days and the finished engravings for which I have already by me, I 

 have given the following most important additions which I have lately 

 made on the same subject. Hitherto I had only been able to observe 

 in the ventral animalcules (^Polygastrica) the motive and nutritive 

 organs, and the ovarium. I had found traces of eyes only in one genus, 

 namely in the genus Eugleiia. I have lately found them more often in 

 the same class, so that I can now name seven genera possessing them 

 which contain sixteen species. Among these forms are some monads 

 which are only y^^ li"- ^^ diameter. From this discovery then the traces 

 of an isolated nervous system are demonstrated down as far as the monads. 



* This latter sentence, the restricting of the generatio primitiva to the for- 

 mation of eggs, appears to me to be moditied by my subsequent observations 

 of tlie development and astonishing productiveness of the infusoi-ia ; for it now 

 appears to be a subject of much greater wonder why we do not find more infu- 

 sorial eggs in water and everywhere, since there is cause for the formation of 

 an innumerable quantity in the common way. 



