350 



ON THE RESPIRATION OF PISIlEy. 



formed a re- 

 cinoamer. 



Fine yellow 

 dye. 



yellow resiniform substance, which dissolred during th« 

 process. On evaporating to dryness I obtained a resinoa- 

 mcr substance of a very pure yellow, fusible at a gentle 

 heat, uniting with alkalis, soluble in alcohol and in boil- 

 ing water,' and falling down in part from the latter on 

 cooling ; soluble in part too in a large quantity of cold 

 water, and communicating to its solutions a very fine yellow 

 colour, which adheres very tenaciously to the fingers, and 

 is easily fixed on wool and silk, giving them a fine lustre 

 unalterable by oximuriatic acid, and even by weak alkalis : 

 consequently there is nothing that can be compared with it 

 for permanence among the majority of dyeing drugs. I 

 may add too, that this yellow appears to me to merit the 

 preference before others in point of cheapness, considering 

 the small quantity of it required. 



This substance, mixed with gum, might yield a more 

 pure and permanent yellow than gamboge. 

 Component From this examination of gum ammoniacum it follows, 



parts of aaamo- (hat 100 parts are composed of 

 niacum. 



IV. 



On the Mechanism of Respiration in Fishes : by 

 Mr. C. Dum^ril, Professor at the Medical School, i^c* 



Themecha- ^^ ^^^se papers I intend to explain some ideas respecting 

 nismof respi- the act of respiration in fishes; to demonstrate, that the 

 similar to that mechanism by which water is drawn into the mouths of 

 of some rep- these animals is precisely similar to that of the respiration of 

 ^* some reptiles; and that, in consequence of this mode of 



respiration, the seat and perception of the organ of smell 



* Mag. Encyclop. Nov. 1807, p. 35, 

 A^ugust the 10th. 



Read to the Institute 

 In 



