FROM SIMPLE PERCEPTIBLE MATTER. 561 
behind an empty egg-shell, a true chorion, I had previously made with- 
out a knowledge of the original observer; and I had even remarked 
that the eggs were suspended by delicate threads, by means of which 
they were carried about by the animalcule, as in the crabs. I noticed 
also the entire intestinal canal, by means of the whirling of the mouth 
aperture and the secretions of the anal aperture; and, in the wheel ani- 
malcules (otatoria), when it was completely filled, its whole course. 
Some time after I also occasionally perceived traces of beautiful red- 
coloured eyes in the wheel animalcules and Brachione; and recognised 
more and more clearly a masticating apparatus in all the forms which 
I examined, and free muscles insome. In 1827 my views respecting the 
wheel animalcules had made a progress to the extent which is represented 
in the third and sixth plates of the Phytozoa of my Symbole Physice. The 
same decade of engravings I laid before the Association of Naturalists 
in Berlin in 1828, but without text. I had used Bory de St. Vincent’s 
nomenclature in these plates, although I did not approve it, solely 
because I considered the innovations required by my observations 
as a useless increase of synonyms until they had been brought to 
maturity. 
The reputation of Chevalier’s microscope, from Selligue’s intimation 
that at a cheaper rate it would produce greater effects than those in 
general use, induced me‘to purchase one in 1828 ; and with it I endea- 
youred to arrive one step nearer to that physiological goal which I had 
so unremittingly pursued during ten years. A review of the Infusoria 
showed me not only that my earlier observations were no delusions, 
but confirmed them, and inereased my conviction of their evidently 
high organization; I convinced myself especially that the supposed 
traces of eyes in some wheel-infusoria, Rotifer and Brachionus, were 
distinct and constant. Being now accustomed to this new instrument, I 
made great use of it on the journey to Siberia which I made in 1829 
with Alexander von Humboldt: the extensive series of accurate ob- 
servations, drawings, and measurements made during this journey, al- 
lowed me, as soonas I returned to Berlin, to institute, with the greatest 
advantage, comparisons with the observations, formerly made in Leip- 
zig, Berlin, Africa, and Arabia: and as I had now no longer any fear 
that the advocates and invstigators of the generatio equivoca might 
be in possession of better instruments; having, moreover, already pos- 
sessed myself of a most astonishing series of details of structure, I 
became gradually convinced of the probability of an. universal high 
organization, even in the infusoria, and so-called elementary molecules; 
of their cyclical, development, and of the numerous errors of earlier 
observers. I found especially the great incongruity between the state- 
ments respecting generation and structure, made by those who pretended 
to have actually seen the generatio primitiva, and who stated that they 
had observed the spontaneous origin of organic bodies from primitive 
