 He begins with a wide generalization about all birds, followed by a ‘more and less’ correlation between the size of the bird and the rate of development. This device allows Aristotle to use the careful description of the chick egg opened on day four as a universal description of development; the reader is licensed to infer that the same stage of development will occur in all birds, but may occur either earlier or later, depending on whether they are larger or smaller than the domestic chicken. Aristotle’s description of this classic experiment led to its being repeated many times in the  Renaissance.[11]  Anyone who has seen modern films of the chick at this stage of differentiation can appreciate the accuracy of Aristotle’s description, especially when one takes into account the size of the chick embryo at this stage of growth.