FRONf SIMPLE PERCEPTIBLE MATTER. 561 



beliind an empty cgg-slitll, a true cliorion, 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 {Rotatoria), 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 Brachionce; and recognised 

 more and more clearly a masticating apparatus in all the forms which 

 I examined, and free muscles in some. 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 thePliytozoa o{mjSi/?nbola:Phi/siccE. The 

 same decade of engravings I laid before the Association of Naturalists 

 in Berhn 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- 

 voured 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 increased 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 soon as 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 cequivoca 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 (jeneratio primiliva, and who stated that they 

 had observed the spontaneous origin of organic bodies from primitive 



