CHEMICAL SCIENCE. 253 



these fluids undergoing distinct and very remarkable histomorphosis. 

 In regard to this interesting phenomena, M. Melsens says : " We 

 know that many feeble acids do not precipitate albumen from its 

 solution ; my experiments have reference especially to the trihydrated 

 phosphoric and acetic acids ; this ceases to be the case when albumen 

 is present with those salts which have no apparent chemical action on 

 it ; the reactions change for acetic acid as well as the phosphoric, with 

 their equivalents of base, and some acid phosphates as well, precipitate 

 it more or less completely. The following is the process by which I 

 prepare the salified solution of albumen : The white of an egg 

 is mixed with its volume of water and filtered ; this constitutes the 

 normal solution of albumen, with a specific gravity of 1,020. The 

 filtered liquor is saturated with salts, which are added in excess, after 

 which the fluid is filtered again, to separate the excess of salts ; the 

 fluid resulting from this second filtration, may be denominated 

 the normal saturated albumen. The normal albumen saturated with 

 chloride of sodium has a specific gravity of about 1,200." 



My experiments have been made with almost all the salts which are 

 without an apparent action on albumen, as well as with those which 

 begin to precipitate it, but whose precipitations are soluble either in 

 an excess of albumen or of the salt. I will not pronounce on the 

 nature of the precipitates obtained ; but it will appear evident that we 

 must in the generality of cases admit, that the albumen is precipitated 

 in consequence of a particular physical disposition of the liquid ; that 

 if at times the precipitation does not occur immediately, in dilute 

 liquor for example, agitation may cause a troubled condition of the 

 fluid, as occurs in precipitation, crystallization, solidification of water, 

 of sulphate of soda, &c. Tribasic phosphoric acid precipitates normal 

 albumen saturated with salts ; certain salts, among which are borax, 

 phosphate of soda, acetates of soda, and potassa, form an exception to 

 this rule ; however, if the fluid be agitated with a glass rod, a troubled 

 condition is slowly produced by the mechanical action. The solutions 

 of albumen with other salts are all precipitated by phosphoric acid ; 

 these precipitates are soluble in an excess of the acid. The presence 

 of the salts, therefore, permits us to make with albumen and the tri- 

 hydrated phosphoric acid an experiment which requires with normal 

 albumen, the monohydrated phosphoric acid which precipitates it, and 

 the trihydrated, w r hich dissolves the precipitate formed. 



" If," says M. Melsens, " after the preceding experiments I am 

 induced to believe that the particular physical constitution of the 

 liquids plays some part in the precipitation of albumen, those which 

 follow cannot leave the least doubt as to the action of agitation. Some 

 very dilute liquids remain limpid until beaten with a glass rod, when 

 they become troubled, and immediately parcels of fibres may be 

 seen to form under the influence of agitation ; under the microscope 

 these appear as very distinctly organized forms, which by juxta- 

 position and felting together constitute actual membranes. We 

 have thus a phenomena conformable to the production of mineral 

 precipitates by the influence of agitation. In another experiment 



