462 Proceedings of PM/osophical Societies. [JuNK, 



case with respect to that part of his work in which M. GeofFroy 

 combats the existence of a lower larynx in birds ; not that he 

 denies that they have at the bottom of their tracheee organic dis- 

 positions which produce sounds ; he only means to say that 

 these dispositions do not consist in parts similar to those of the 

 upper larynx, which no person indeed had ever ventured to 

 assert. 



The theory peculiar to M . GeofFroy of the voice and of sound 

 is not necessarily dependent on his anatomical researches ; it is 

 the result of some ideas of general natural philosophy, which he 

 long since formed, but which he has not, on the present occa- 

 sion, developed sufficiently to allow of our giving an account of 

 it. We shall merely say, he considers the thyroid cartilage as a 

 sonorous body, which serves as a table of harmony to the vocal 

 instrument, and attributes to the variation of the distance between 

 this cartilage and the os hyoides the variations of tone. 



This volume is terminated by a memoir on the bones of the 

 shoulder. The author long ago made known the resemblances 

 of these bones in fishes to analogous bones in birds, and he has 

 indeed been led by this circumstance to make all those researches 

 on comparative osteology, of which we have more than once 

 spoken to our readers. He has resumed this subject in a more 

 general point of view, and considers these bones as having 

 attained in fish their maximum of development and importance, 

 by serving as a shield to the heart, a support to the diaphragm, 

 and a stretcher to the gills. 



To conclude, we shall here repeat the invitation we have 

 already given to naturalists, to consult a work filled with new 

 and interesting facts, and from which much may be learned 

 even on those points, respecting which we may not be able to 

 adopt all the opinions of the author. 



M. Edwards has continued the curious experiments which he 

 began last year on the respiration of frogs ; he had then con- 

 vinced himself the presence of air is useful in prolonging the 

 life of these animals, when circulation and pulmonary respiration 

 have ceased ; that water causes them to perish more quickly than 

 a solid covering, and the more quickly in proportion as it is less 

 impregnated with air ; and he has this year occupied himself 

 more particularly about the influence of the air contained in 

 water, and that of the temperature to which this liquid is raised. 

 He has proved that the deleterious efi^ects of the water diminish 

 with the temperature. Frogs have lived twice as long in water 

 at 10° (50'^ Fahr.) as in water at 15° (69° Fahr.), and thrice as 

 long in water at 0° (32° Fahr.). On the contrary, their life is 

 shortened by nearly one half at 22° (72° Fahr.) by more than 

 three quarters at 32° (90° Fahr.) and they perish instantaneously 

 upon being plunged into water at 42° (107° Fahr.) The coldness 

 of the atmosphere before the operation is also a circumstance 

 favourable to the lenothenino; of their existence in cold water. 

 The quantity of air contained in the water, the volume of the 



