•■">.5S DOCTniNE OF SPONTA?<KANS DISPUOVEn. 
that monads are not produced from parents, but by some process of 
chemistry or they kno.w not what. Now M. Chrenberg has disco- 
covered that these monads do spring from parents, in a similar man- 
ner to lai'ger animals. The following is Baron Cuvier's report of the 
discovery : 
"The work which M. Hiunboldt presented to the academy, on 
the part of its author, M. Chrenberg, and which treats upon animal- 
cules known under the name of microscopic and infusoria is a valu- 
able acquisition to zoology. Not only has M. Chrenberg made 
many observations respecting these animalcules during his travels 
into Egypt and Nubia, and determined European species, which are 
also found in those distant regions — not only has he established new 
methodical distributions in this remarkable class, and added numer- 
ous new species, but he has effected a discovery which must produce 
a gi-eat change in the ideas previously entertained respecting their 
organization. On tinging water, inhabited by these animals, with 
unadulterated organic colouring matters, such as indigo, carmine, 
sap-green, he was enabled to render their alimentary canal distinctly 
visible, and ascertained that not a single species is supported by the 
intus-susception of its surfae, but that all have an intestinal canal ex- 
ceedingly complicated, convoluted, and furnished with stomachs and 
sometimes very numerous coeca. In some he perceived special or- 
gans of propagation, and traces, likewise, of a nervous and muscular 
system. Naturalists had already admitted the existence of interior 
organs, and particularly a stomach, in the largest sized animals of this 
class, as for example in the wheel animalcule, (rotifere;) but we are 
not aware that any one before M. Chrenberg, ever doubted the exis- 
tence of a digestive canal, and stomachs in those species, which ai'e 
simply regarded as homogeneous and gelatinous amongst those 
monads, of which many thousands are contained in a drop of water. 
This discovery entirely changes received opinions, and demolishes 
many systems ; and is one of those discoveries which fonn a remark- 
able epoch in scientific researches. — Annales des sciences JVaturelles 
pour JVovr. 1831. 
.J. R, 
