154 Prof. A. Gamgee and Dr. E. Blankenhorn. [June 19, 



prove the definite nature of protagon by a large number of analyses, 

 indicating not merely the amount of phosphorus, but also that of the 

 other elements present in it. 



This investigation we have lately been able to carry out with all 

 necessary minuteness, and having, to our entire satisfaction, established 

 the real existence of protagon, we communicate the results obtained 

 before proceeding to a fresh study of the products of decomposition of 

 that body. 



Process employed in the preparation of Protagon in the present research. 

 At first we commenced by repeating exactly the process of Liebreicb 

 in all its details ; one of the steps of that process we had found fraught 

 with peculiar difficulty, and we soon ascertained that it could be dis- 

 pensed with without prejudicially affecting the success of the opera- 

 tions. The step to which we refer consists in agitating the freshly 

 pounded brain repeatedly with water and ether at 0° C, so long as the 

 ether dissolves considerable quantities of substance, then filtering and 

 placing the insoluble matter into 85 per cent, alcohol at 45° C. When 

 pounded brain is so treated with water and ether it swells up and the 

 separation of the ether is most incomplete. The process of filtration 

 is one which is attended with great difficulty, even when carried out 

 in the only way in which we found it possible, viz., in the woven bags 

 sold for household purposes for straining jellies, &c. By the kindness 

 of Professor Osborne Reynolds, F.R.S., a small model of a centrifugal 

 hydro-extractor, similar to that used in sugar refineries, was con- 

 structed for us in the engineering workshop of the Owens College, 

 and was driven by the laboratory steam-engine, and this was for 

 some time efficiently employed in separating the portion of the brain 

 insoluble in water and ether from these fluids. It was, however, 

 obvious that however prolonged the ether washing, it never succeeded 

 in freeing the brain from cholesterin and other matters soluble in 

 ether, and that the removal of these bodies from protagon was most 

 readily effected at a later stage of the operations. As, ultimately 

 modified, our process was as follows : — 



Perfectly fresh ox's brains were freed from blood and from adhering 

 membranes as completely as possible, and were then digested for 

 many hours (18 to 24) in 85 per cent, alcohol in a large incubator 

 kept constantly at 45° C. The fluid was filtered whilst hot, and the 

 insoluble matter was again treated with fresh quantities of spirit, the 

 proceeding being repeated four or five times, as long, indeed, as the 

 filtrate when cooled to 0° deposited a fair quantity of white flocculent 

 precipitate. This precipitate was collected on a filter, and being then 

 transferred to a stoppered bottle was thoroughly and repeatedly 

 agitated with ether, in order to dissolve cholesterin and other bodies 

 soluble in ether. The ether having been removed, first by decantation 



