THE OSTRICH. 217 



doubtless due to a physiological phenomenon, which is 

 common to birds which rise into the air, viz., that 

 not only are the greater part of its bones vacuous, and 

 in direct communication with the lungs, but the bird 

 can also at will fill with warm air many membranous 

 reservoirs, which are found near the wings, under the 

 stomach, and around the thighs veritable air balloons, 

 which lighten the weight borne by the legs. When it 

 is not racing or otherwise excited, these sacks are not 

 inflated, and consequently the ostrich cannot support 

 so considerable a weight. 



VI. 



speed of the animal does not yield to its strength. 

 Cuvier says that it surpasses that of all known 

 animals. "It is such," adds he, "that those who 

 mount the ostrich without having become accustomed 

 to it, are soon suffocated, not being able to get their 

 breath." This nearly happened to an inhabitant of 

 Paris, M. Notre, who being at Marseilles in the 

 year 1819, then weighing 1401bs., mounted a male 

 Egyptian ostrich of large size. It took him such an 

 astounding race, that he contemplates it even to this 

 day with affright. Happily, he clung tightly round the 

 neck of the bird, which at last stopped in some brush- 



