 There are a number of features in this passage that are common throughout the Historia Animalium and provide insight into its methods and aims. First is the syntactically redundant linguistic pattern hosa…panta (“as many as...all”), variants of which are common in this treatise. Aristotle appears to use the sentence form “As many as are X, all have Y” for a quite specific reason. It is not just to note a universal correlation; it is to do so while leaving the extension of the correlation open—a brilliant methodological innovation. New animals with the correlation can be discovered, but the generalization will not change, since it is about the universal correlation among differentiae—in this case internal organs—not about the kinds that exemplify it. It appears that when Aristotle intensifies the expression by writing panta hosa, as he does once here, he means to signal a convertible universal, an ‘entailment’ as we would say. Aristotle first lists a number of distinct groups, all the members of which have the three organs being discussed, windpipe, lung and esophagus. Then, using the term ‘generally’ to signal what he is about to do, he identifies a differentia that all these groups have in common, and which is coextensive with these three organs—inhaling and exhaling air. The inductive pattern has the following form: