560 EHRENBERG ON THE ORIGIN OF ORGANIC MATTER 
pound microscope from Nurenberg, which I had, according to my own 
views and wants, rendered more powerful, the same indeed with which 
I had already discovered the germination of the seeds of moulds, which 
however was far inferior to the ingenious microscopes of that time. 
Those observations appeared, however, to my friend to be so unques- 
tionable, that he would not forego the opportunity of making known the 
principal points in his book. 
From 1820 I made my observations in Africa with a microscope 
made by Hofmann of Leipzig, of the cost of about £6, which, with a 
greater magnifying power, gave a much better image; and from the 
year 1824 I used together with that an English microscope by Bleuler, 
which cost about £15, and the power of which was still higher. With 
these instruments I followed up the critical investigation of the generatio 
primitiva with increasing care; and the more exact my observations 
were, the colder I became towards the idea of an instantaneous coagu- 
lation of primitive substances into an organized being. In the whole 
series of years, during which I have sometimes for days together conti- 
nued those observations, I never, not even in a single instance, saw the 
subitaneous origination from slime, cellular tissue of plants, &c., of those 
minute organic bodies to me so well known; still much less had I ob- 
served the gradual development of elementary outlines that had suddenly 
originated, of Entomostrati and other larger animalcules ; which was an 
extraordinary delusion of M. Fray, who took the exuvie and fragments 
of minute dead animals for sketches and rudiments of new generations *. 
My observations pursued in Africa convinced me more and more 
that the origin of the most minute organized beings must also be cycli- 
cal; for although circumstances did not enable me there to bring to a 
completion my investigations into the structure of the Infusoria, yet I 
found always amanifest repetition of forms similar to those which I had 
determined by drawings and measurements, and not at all that unlimited 
variation of them which we should expect from the idea of a metamor- 
phosis of destroyed organic substances into undetermined elementary 
forms of life. Thus the basis on which my observations proceeded 
continually became firmer. Corti’s discovery, that the eggs of some 
Infusoria (Brachionus) burst when the young ones creep out, and leave 
* Essai sur UV Origine des Corps organisés et inorganisés, par Fray. Paris, 
1817; p.71. “J'ai vu des monocles, des polypes, des vers et d'autres animaux, 
qui n’ étaient encore qu’ébauchés ; la forme extéricure était jelée, mais L’inté- 
rieur n’avait pas recu tous les globules actifs qui devuient le constituer. Ces 
esquisses étaient encore immobiles.” This puts one in mind of the celebrated 
ancient Egyptian frogs, which were said to come into existence after the inun- 
dation, and to hop about with only their fore part developed, while their hinder 
part was still mud. Times are altered; for he that sees such frogs at the present 
time, does not, even in Egypt, stand with trembling awe at a distance from them, 
but lays hold of them, and finds that under the mud of the hinder part some- 
thing more than outlines are hidden. So it was with me at the Nile; for I came 
there indeed as a sceptic. 
