64 iii. 3- 



condition the Fishes are an example. The other part, or 

 CESophagus, is the channel through which food is conveyed .to 

 the stomach ; so that all animals that are without a neck are 

 also without a distinct oesophagus. ^ Such a part is in fact not 

 required of necessity for nutritive purposes ; for it has no action 

 whatsoever on the food. Indeed there is nothing to prevent 

 the stomach from being placed directly after the mouth. This 

 however is quite impossible in the case of the lung. For there 

 must be some sort of tube common to the two divisions of the 

 lung, by which the breath may be apportioned to their respective 

 bronchi, and thence pass into the air pipes ; and such an arrange- 

 ment will be the best for giving perfection to inspiration and 

 respiration. The organ then concerned in respiration must of 

 necessity be of some length ; and this again necessitates there 

 being an oesophagus to unite mouth and stomach.^ This 

 oesophagus is of a flesh-like character, and yet admits of exten- 

 sion like a sinew. ^ This latter property is given to it, that it 

 may stretch when food is introduced ; while the flesh-like 

 character is intended to make it soft and yielding, and to 

 prevent it from being rasped by particles as they pass down- 

 wards, and so suffering damage. On the other hand the windpipe 

 and the so-called larynx are constructed out of a cartilaginous 

 substance. For they have to serve not only for respiration, 

 but also for vocal purposes ; and an instrument that is to 

 produce sounds must necessarily be not only smooth but firm. 

 The windpipe lies in front of the oesophagus, although this position 

 causes it to be some hindrance to the latter in the act of 

 deglutition.^ For if a morsel of food, fluid or solid, slips into 

 it by accident, choking and difficult breathing and violent cough 

 ensue. This must be a matter of astonishment to any of those 

 who assert that it is by the windpipe that an animal imbibes 

 fluid. ^ For the consequences just mentioned occur invariably, 

 whenever a particle of food slips in, and are quite obvious. 

 Indeed on many grounds it is ridiculous to say that this is the 

 channel through which animals imbibe fluid. For there is no 

 passage leading from the lung to the stomach, such as the 

 oesophagus which we see leading thither from the mouth. 

 Moreover, when any cause produces sickness and vomiting, it is 

 plain enough whence the fluid is discharged. It is manifest also 

 that fluid, when swallowed, does not pass directly into the bladder 

 664b. 



