56 ORGANS OF BREATHING. 



the water up the nostrils. But the Gannet has nothing- 

 to fear from either of these causes, the front of its head 

 being covered with a sort of horny mask, which gives it 

 a singularly wild appearance ; and it has no nostrils, a 

 deficiency amply remedied by the above-mentioned re- 

 servoirs of air, and capacity for keeping them always 

 filled. Some notion may be formed of the rapidity of 

 their descent by a curious mode of taking them, occa- 

 sionally practised by the fishermen in the North. A 

 board is turned adrift, on which a dead fish is fastened. 

 On seeing it, the Gannet pounces down, and is frequently 

 killed or stunned by striking the board, or is secured by 

 its sharp-pointed beak being actually driven into the 

 wood like a nail and holding it fast. 



There is another bird even more copiously supplied 

 with air than the above, called the Chavana Fidele, in 

 which the skin is entirely separated from the flesh, and 

 filled with an infinity of small air-cells, the legs and even 

 toes partaking of the same singularity, so that it appears 

 much larger than it really is, and when pressed by the 

 finger, the skin sinks in, but resists pressure like a foot- 

 ball, or other elastic body. The air, in this case, is 

 supposed to assist in producing a powerful screaming 

 voice, the bird being a wader, and not calculated for 

 lengthened flights. 



Generally speaking, the bones of birds, excepting 

 when young, are without marrow, the gradual absorp- 

 tion of which, till the bones become a hollow tube, is 

 most easily perceptible in young tame Geese, when killed 

 at different periods of the autumn and winter. From 

 week to week the air-cells increase in size, till, as the 

 season advances, the air-bones become transparent. 

 Towards the close of the summer and beginning of 

 autumn, although in external appearance the young 

 Goose resembles the parent, no trace of air-cells can be 

 discovered in its bones, the interior being still filled 

 up with marrow, which does not entirely disappear till 

 about the end of the fifth or sixth month. 



