526 



Mr. G. S. Johnson. 



(2.) Efflorescent kreatinin ft, which, having effloresced, recrystal- 

 lises in the tabular anhydrous form from cold aqueous solution. 



(3.) Tabular kreatinin a., which recrystallises in the same form 

 when its cold aqueous solution is evaporated in vacuo over sulphuric 

 acid. 



(4.) Tabular kreatinin ft, which recrystallises in the efflorescent 

 form when its cold aqueous solution is spontaneously evaporated. 



There is no apparent difference between the crystals of (1) and (2), 

 nor any between those of (3) and (4). Yet, when the conditions of 

 solution and evaporation are kept as similar as possible, there is the 

 remarkable difference described in the products of re-crystallisation. 

 These four substances may be obtained as follows : — 



(1.) Efflorescent kreatinin a is the product usually obtained after 

 the treatment of the kreatinin hydrochloride, prepared from urinary 

 kreatin, by Liebig' process, with pure lead hydrate at the ordinary 

 temperature. After it has effloresced, we may obtain from it either 

 (3) or (4). 



The tabular kreatinin ex. is formed if the solution of the effloresced 

 crystals is made at 100° C, even though the subsequent evaporation 

 be conducted at the ordinary temperature. 



The tabular kreatinin ft is the product if the effloresced crystals are 

 dissolved in water at 60° 0. 



The weight of both these forms of crystals is always identical with 

 that of the effloresced kreatinin from which they were obtained. 



(2.) Efflorescent kreatinin ft is obtained by dissolving tabular 

 kreatinin a in water at 60° C, and then subjecting the solution to 

 evaporation in vacuo over sulphuric acid. Efflorescent kreatinin is 

 never obtained by deposition on cooling from a hot solution. 



Erom tabular kreatinin oc tabular kreatinin ft is obtained by dis- 

 solving in boiling water, and then evaporating the solution at the 

 ordinary temperature. 



The following are some results of re-crystallisation of artificial 

 urinary kreatinin : — 



Nature of crystals. 



Dissolved in 



Evaporated. 



Product. 



Tabular K 



Water at 60° C. 



In vacuo . . . 



Efflorescent Ky3. 





Efflorescent K/3. . 



Cold water. . . . 



Do. ... 



Tabular Zj3. . 



Tabular Kf3 . . . . 



Do 



Do. ... 



Efflorescent Ka. 



In this case alternate crystallisation of tabular and efflorescent 

 kreatinin took place twice, the kreatinin becoming finally permanently 



