For Nature is accustomed to rehearse with certain large, perhaps baser, and all classes of wild (animals), and to place in the imperfect the rudiments of the perfect animals.

Observation by means of the microscope will reveal more wonderful things than those viewed in regard to mere structure and connection: for while the heart is still beating the contrary (i.e., in opposite directions in the different vessels) movement of the blood is observed in the vessels-though with difficulty-so that the circulation of the blood is clearly exposed.

Surgical knowledge depends on long practice, not from speculations.

It is therefore proper to acknowledge that the first filaments of the chick preexist in the egg and have a deeper origin, exactly as [the embryo] in the eggs of plants.

In such sad circumstances I but see myself exalted by my own enemies, for in order to defeat some small works of mine they try to make the whole rational medicine and anatomy fall, as if I were myself these noble disciplines.

This, however, seems to be certain: the ichor, that is, the material I have mentioned that finally becomes red, exists before the heart begins to beat, but the heart exists and even beats before the blood reddens.

Nature has but one plan of operation, invariably the same in the smallest things as well as in the largest, and so often do we see the smallest masses selected for use in Nature, that even enormous ones are built up solely by fitting these together. Indeed, all Nature's efforts are devoted to uniting the smallest parts of our bodies in such a way that all things whatsoever, however diverse they may be, which coalesce in the structure of living things construct the parts by means of a sort of compendium.