1813.] and some other Animatsi _ S3f 



no indication of the presence of ammonia. Even a boiling 

 heat did not develope tiie smallest trace of this alkali. In this 

 experiment I was very much surprised to perceive, that though I 

 had employed a quantity of potash more than sufficient to 

 dissolve a quantity of tallow, more than I employed, yet the 

 solution did not take place; and the mixture remained as milky 

 as if water had been employed instead of potash. 



I think we may conclude from these experiments that the 

 fatty matter from the brain contained neither phosphoric acid 

 nor phosphate of ammonia, and that the acid which appear^ 

 after the combustion had another origin. 



3. A hundred parts of the fatty matter of the brain were 

 heated in a platinum crucible, with 200 parts of potash, and ai 

 little water. The mixture did not melt ; but, on the contrary^ 

 became harder, which would not have happened if the substance 

 in question had been real tallow. When the humidity was 

 dissipated it assumed a brown colour, took fire, emitted an odour 

 of burning grease, and gave out a great deal of smoke. The 

 residue of this operation was washed with distilled water ; the 

 liquid being saturated with nitric acid, and boiled, gave, when 

 mixed with lime-water, a flocky precipitate, which was phosphate 

 of lime, and which weighed^ when dry, tiie tenth part of the 

 mass employed. 



4. A hundred parts of the same matter thrown successively 

 into melted nitre took fire with great facility, producing scarcely 

 any smoke, the whole was destroyed, and nut the smallest trace 

 of charry matter remained. The residue of this operation, 

 treated in the same manner as the preceding, gave the same 

 quantity of phosphate of lime. 



What conclusion can be drawn from these experiments, 

 except that there is phosphorus combined w^ith the fatty matter 

 of the brain, and which dissolved in alcohol at the same time 

 with the fatty matter ? We find in the residue after combustion 

 neither phosphate of lime nor phosphate of magnesia. The 

 alkaline phosphates would have found enough of water in the 

 brain to remain in solution in the alcohol, and not to precipitate 

 when the liquid cools. Accordingly Vve find phosphate of pot- 

 ash, superphosphate of lime and of magnesia, in the residue of 

 the alcohol evaporated, which had been digested with the 

 cerebral matter. We must therefore admit the existence of 

 phosphorus in the brain, as well as in the roes of fishes, v/here 

 it was discovered by Fourcroy and me. The pj'oportion of it, 

 indeed, is very small; for from the quantity of phosphate of 

 lime which I obtained in the preceding experiments, I estimate 

 its quantity not to exceed ^-§-^ths of a part : bat if we subtract 

 the humidity of the brain, and only consider the dry residuam, 



VoL,I. N<^V. Y 



