REVERSION OF HYDROLYSIS 431 



stance was obtained from the gram of paranuclein originally 

 dissolved in the lime-water. 



The splitting off of phosphorus from paranuclein in alkaline solu- 

 tion has been commented on by other observers (61). 



The substance which is obtained synthetically, as described 

 above, resembles paranuclein A very closely both in general prop- 

 erties and in its percentage-content of P2O5. The synthesized 

 substance is insoluble in dilute weak acids, readily soluble in 

 dilute alkali, precipitates protamin from a 1 per cent solution of 

 the sulphate at a reaction just alkaline to phenolphthalein (at 

 which reaction both the protamin and the paranuclein remain 

 in stable solution when not mixed), and a 2 per cent solution in 

 N/10 sodium hydroxide is precipitated by m/10 ferric ammo- 

 nium sulphate; these being all well-known properties of para- 

 nuclein (61) (42). 



The synthesized substance also resembles my preparation of 

 paranuclein A in the following properties; in approximately 

 2 per cent solution in A^/100 NaOH it gives the xanthoproteic, 

 Millon's, Adamkiewicz and the biuret (violet) reactions; it is 

 precipitated by cupric chloride (1 vol. of N/1 to 100) and by 

 zinc chloride, but not by mercuric chloride (5 vols.; of iV/10) 

 it is precipitated by picric and tannic acids, but the precipitate 

 redissolves on rendering the solution alkaline; it is not precipi- 

 tated by the addition of five volumes of absolute alcohol; and 

 the precipitate which is at first produced by the addition of acetic 

 acid is soluble in considerable excess of the reagent. 



The change in the refractive index of iV/50 KOH which is 

 brought about by the introduction of one per cent of the synthetic 

 substance is identical with that which is brought about by the 

 introduction of one gram of paranuclein or paranuclein A (54), 

 namely, 0.00140 for sodium light. 



If no pepsin be added to the concentrated solution of the 

 products of the peptic digestion of casein, prepared as described 

 above, the solution, after keeping for over a year at room-tem- 

 peratures or for several months at 40° C. remains perfectly clear 

 and homogeneous and gives no tests for paranuclein or for casein. 

 A 10 per cent filtered solution of Gruebler's pepsin, on standing 

 for many months at 40 degrees, also remains perfectly clear and 

 homogeneous. Yet these two solutions, when mixed in the 

 proportion of one volume of ferment-solution to five volumes of 



