562 EHRENBERG ON THE ORIGIN OF ORGANIC MATTER 



substances, or its gradual formation, without however having noticed 

 their complex internal structure ; whilst at the same time, I myself, who 

 for a series of years had acquired a progressively deeper insight into 

 the organization of these minute forms, which were said to be developed, 

 destitute of organs, or imperfect, could never get a sight of their spon- 

 taneous or gradual origin from molecules, slime, vegetable tissue, &c. 



A comparison of my observations on the bell-animalcule ( Vorticella 

 Convallaria and other species of this genus), which had been made 

 under geographical circumstances the most various, greatly confirmed 

 my impressions ; and the repetition, with redoubled care, of my inves- 

 tigations of their gradual individual change, removed all doubts in 

 regard to a whole series of beings of various kinds, in which I disco- 

 vered a determinate cyclus of forms, deriving their origin from one 

 another. These data, of which I became convinced, in beings so 

 minute and so simple in appearance, incited me to direct my observa- 

 tions, with increasing care, to this point, and gave me a certain 

 anticipation of much more interesting results near at hand. High 

 organization, and cyclical development of the molecules, were to me 

 clear truths, floating in my imagination, and capable of more substan- 

 tial proofs : my only search was for the means to produce them. 

 Fortunate was the thought which brought to my recollection the 

 coloured nutritive substances, already often tried by me without suc- 

 cess. Confident of the result, I put various colouring substances into 

 the water containing the infusoria, and awaited their reception into 

 their organs of nutrition. The first experiments with common water- 

 colours failed, although I had selected many different colouring matters; 

 my conviction however of a better result was so strong, that I no longer 

 attributed its want of success to the organization of the animalcules, 

 but to unsuitable colouring matters. Other experiments also proved 

 unsuccessful. One day however I remarked, in experimenting, a 

 whitish sediment at the bottom of the small glass plate on which I had 

 mixed water colours with the water containing the infusoria ; and as 

 in general the colours of the shops are mixed with white lead, I made 

 choice of some pure colours, and such as I supposed to be least 

 disagreeing with animal organization ; such I considered indigo, car- 

 mine, and sap-green, as they are all of purely organic origin. With 

 these I began my experiments anew, and here also the clew was found; 

 all infusoria, even the smallest, soon filled themselves with the colouring 

 matter. The opacity of the water caused by the colour, enabled me 

 to distinguish much more clearly than the opacity caused by mud, 

 which I had made use of in my former experiments on the cilia, not 

 only the presence of the cilia, but also any separate part of the body 

 to which the vortex caused by the cilia carried the nutritive particles, 

 and where they were received into the interior of the body. 



From the transparency of all these animalcules, I could see very 



