1879.] 



On Liebreiclis Protagon in the Brain, 



155 



sistence of a thin milk and then boiling ; a precipitate forms, which is 

 extracted with boiling alcohol. On cooling, the fluid deposits an 

 abundant precipitate ; this is treated with ether, to separate choles- 

 terin and fats, and then recrystallized from boiling alcohol. Of this 

 body Miiller published two analyses, which led him to assign to it the 

 formula Cg^HggNOg. It is described by Hoppe-Seyler as a light, 

 white, highly hygroscopic powder.* 



But what right have we to assume that a body obtained by boiling 

 so complex an organic mixture as a brain with caustic baryta is a 

 proximate principle of the brain, i.e., that it exists preformed in the 

 brain ? The surmise is as bold as it is improbable. 



Lecithin is described by Diaconow himself as a non-pulverizable, 

 yellowish-white, highly hygroscopic body.f Is it not strange that two 

 usually amorphous highly hygroscopic bodies should, when mixed, give 

 rise to a constantly crystallizable absolutely non-hygroscopic mixture ? 

 And this is exactly what would be the case were the hypotheses of 

 Diaconow and Hoppe-Seyler correct. 



According to Diaconow, by repeated extractions with ether, the P 

 contained in protagon may be made to sink to 1 per cent., whereas, 

 according to Liebreich's formula, it should contain 1*5 per cent. 

 Actually, in the three determinations which he made, Liebreich 

 obtained 1*1, 1*1, and 1*5, as the amount of phosphorus in 100 parts, 

 but, unfortunately, Tie seems to have concluded that the highest number 

 was correct and made it the basis of his calculation. 



In the year 1877, one of us, assisted by Mr. Leopold Larmuth, 

 Piatt Physiological Scholar, commenced in the Physiological Laboratory 

 of Owens College, a series of experiments intended to determine whether 

 Liebreich's protagon existed or not. This preliminary investigation 

 showed that by Liebreich's process there is always obtained a body 

 having the physical properties of protagon, and containing phosphorus 

 in a proportion sufficiently near to that indicated by him; it was found 

 that the amount of phosphorus in specimens of protagon which had 

 been crystallized from alcohol four or five times, was not smaller than 

 that present in protagon which had only once been crystallized, though 

 a thorough treatment with ether preceded each recrystallization. 



These first experiments so far as they went, were perfectly satis- 

 factory. It appeared, however, quite essential, before forming a 

 definite opinion, to extend them very considerably and especially to 



* " Auf diese Weise dargestellt bildet das Cerebrin ein leicbtes weisses sebr hy- 

 groscopisches Pulver," &c. Hoppe-Seyler, " Handbuch der Pbysiologisch — und 

 Pathologiscb — Cbemischen Analyse." Dritte Auft. S. 169. 



f " Das reine Lecitbin stellt eine gelblicb-weisse, wachsartige, in diinner Scbicbt- 

 ausgebreitet seiden-glanzende, sebr bygroscopiscbe Masse dar." Diaconow, " Ueber 

 die Cbemiscbe Constitution des Lecithin." " Centralblatt f. d. Med. Wissen- 

 scbaften," 1868, p. 2. 



