472 Miscellaneous. 



vivisections, aided by touch and anseultation, proved to him abso- 

 lutely that the muscles themselves are the agents producing the vibra- 

 tions from ivhich the sounds formed originate (loc. cit. 1862, p. 394). 

 Since then a distinguished physiologist, M. Armand Moreau, by sub- 

 mitting the nerves which run to the air-bladder of the gurnards to 

 the action of an electric current, has ascertained that the striated 

 muscles of the air-bladder contract and cause the reproduction of 

 the characteristic sounds, and this in the animal when killed by 

 section of the spinal cord (Comptes Kendus, 18G4, tome lix. p. 437). 

 This mode of formation of sounds by contraction of the muscles 

 of the air-bladder was not known before the investigations of M. 

 Dufosse. Science has to thank him for this discovery, and for the 

 care which he has taken in observing the diversities of this pheno- 

 menon from species to species of the fishes which present it. 



We shall conclude this report by calling the attention of the 

 Academy to another point in this work, because it will certainly 

 become the subject of fresh experiments made by means of the re- 

 gistering and other instruments which now-a-days serve to determine 

 the real nature of a great number of organic phenomena. Accord- 

 ing to M. Dufosse, it is not the readily visible movements of the 

 air-bladder that are the cause of the sound heard while they last. 

 Although much greater than the concomitant trepidations which cause 

 the sonorous vibrations, these contractions merely tighten or relax cer- 

 tain parts of the air-reservoir ; and the use of the latter in this respect 

 is to act as a sounding-board, an organ for the reinforcement of 

 the sounds produced, which are comprised between si^ and r«\ 



It is well known that the striated muscles during contraction 

 give rise to a peculiar sound, which is called the muscidar sound, 

 rotatory sound, susurrus, wrinMing, or myophonia, and has been 

 well studied by WoUaston, Erman, Gilbert, Laennec, and many 

 modern observers. According to M. Marey this muscular sound cor- 

 responds sometimes to the td, and sometimes to the si of the lower oc- 

 tave of the piano. Now, according to M. Dufosse, the noise produced 

 by the fishes of which we are speaking is this very muscular sound, 

 caused by the contraction of the voluntary muscles of the air-bladder ; 

 and the latter plays, with respect to it, the part of an organ of re- 

 inforcement in a suflSciently marked manner to enable it to reach 

 our ears. 



The Academy will see that, if the correctness of this ingenious 

 analysis of the mechanism of production of the sounds produced by 

 the air-bladder should be experimentally confirmed, the acoustic 

 property of muscular contraction will be raised to the height of a 

 phenomenon productive of sounds, not merely commensurable, but 

 even expressive. In the absence of experiments made by your 

 committee, it cannot yet pronounce a formal opinion upon this 

 point. But it recognizes that, by the sagacious and laborious em- 

 ployment of his knowledge of comparative anatomy and physiology, 

 M. Dufosse has discovered new facts which have elucidated several 

 previously obscure ichthyological questions. — Comptes Bendus, 

 November 4, 1872, tome Ixxv. pp. 1074-1078. 



