172 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



is excellent. Although it differs markedly from the type 

 usually present in Birds, they nevertheless distinguish 

 a glandular portion, corresponding to the proventriculus, 

 and a muscular portion, corresponding to the gizzard. 

 Its unusual form they attribute to the piscivorous diet of 

 the species. 



But the bird most grateful to the curiosity of the 

 Parisians, and of which they dissected eight examples, 

 is the Ostrich, and they give a lengthy and • excellent 

 description of its anatomy. They pursue in detail the 

 structure of the feathers, and contrast them with the 

 quill feathers of a flying bird. In this they appear to 

 have been ignorant of the work of Robert Hooke on the 

 morphology of feathers, first published in the Micro- 

 graphia of 1665. They understood the structure and 

 function of the barbs and barbules, and they recognise the 

 double advantage of a concavo-convex feather — its greater 

 rigidity and grip of the air on the downward beat, and 

 its diminished resistance on the upward stroke. They 

 devote ample space to an account of the air sacs, which 

 is on the whole complete and accurate, and they under- 

 stood the connection between the air sacs and the lungs, 

 and how they became filled with air. They regard the 

 jDartitions separating the air sacs as a series of 

 diaphragms, and we note with regret a tendency to go back 

 on their acceptance of the doctrine of the circulation in 

 the description given of the passage of the blood through 

 the lungs. In the section on the brain an incident is 

 mentioned which illustrates how the abuse of advertise- 

 ment betrayed the confidence of mankind in a trusting 

 and superstitious age. To demonstrate the powerful 

 virtues of a healing balsam, its inventor would plunge a 

 knife into the head of a bird, whose life he then professed 

 to restore by the application of his celestial ointment ; and 



