CHEMISTRY. 



119 



" free-nitrogen extract " vary less regularly. 

 Sugars appear in- larger amount in the young 

 plant than in the other stages. The same is 

 the case with the organic acids. 



Animal Chemistry. Accompanying the forma- 

 tion of nitrogenous tissue in the vegetable 

 organism, occurs a corresponding increase of 

 phosphoric acid, and in the excretory products 

 of the animal kingdom a definite quantity of 

 nitrogen has been found to be accompanied by 

 a relative amount of phosphoric acid. Again, 

 when less nitrogen is excreted than is taken in 

 the food, less phosphoric acid is also passed off, 

 and from these data Kossel has inferred the 

 existence of a compound of albuminous matter 

 with phosphoric acid. The nucleins approach 

 nearest to such a composition. Kossel has re- 

 cently undertaken a quantitative determination 

 of nuclein by estimating the nuclein-phosphoric 

 acid. 



His percentages of acid found in various tis- 

 sues are always largest in the case of organs 

 containing most cell-nuclei; thus, in the spleen 

 of the ox was found '636 per cent, of nuclein- 

 phosphoric acid, in the liver '390 per cent., and 

 in the pancreas -580 per cent., while in ox-mus- 

 cle was found only '092 per cent., and inhuman 

 blood merely a trace. It has been suggested 

 that the amount of nnclein might be deter- 

 mined from the quantity of its decomposition 

 products, viz., guanine, xanthine, and hypo- 

 xanthine, but Kossel has found that the quan- 

 tity of hypoxanthine, though in proportion to 

 the quantity of nuclein in some organs, bears 

 no such relation in the muscles ; thus the mus- 

 cle of the fowl yields much hypoxanthine, but 

 has a very small content of nuclein. He also 

 points out that the organs especially engaged 

 in the nutritive and regenerative processes of 

 the body contain far more phosphoric acid in 

 the form of nuclein than the looomotot appa- 

 ratus. Two so-called nucleins, those from cow's 

 milk and the yolk of egg, which do not come 

 from cell-nuclei, differ from those found in liv- 

 ing tissue in yielding no xanthine, hypoxan- 

 thine, or guanine. 



. The exact chernioal nature of the peptones 

 has been much discussed, and no agreement of 

 opinion has been reached upon it. In fact, the 

 numerous results recorded are so strikingly at 

 variance with each other that the theories on the 

 subject have been, from time to time, very much 

 modified. These differences may be partly ac- 

 counted for by reference to the great diversity 

 of conditions under which the experiments have 

 been conducted. According to Berth's analysis, 

 there is but little difference between albumen 

 (Wurz's formula) and the peptone formed from 

 it. From a great number of analyses of pep- . 

 tones prepared by fractional precipitation with 

 alcohol and ether, Herth has drawn conclu- 

 sions in favor of the individuality of the pep- 

 tones, and infers that there is no ground for 

 belief in the theory that they are a mixture of 

 several closely-related bodies. Adamkiewicz 

 concludes from his studies that chemically the 



peptones are nothing but albuminates which 

 differ from ordinary albumen by containing a 

 diminished content of inorganic salts and a 

 somewhat different molecular formation, but 

 the grounds on which he bases his view are 

 controverted by Maly and Herth, who found 

 no evidences of a materially diminished quan- 

 tity of salts ; and Aronson has shown that the 

 uncoagulability of the peptones their most 

 striking feature is wholly independent of in- 

 organic salts. Herth concludes that the analyti- 

 cal data give no idea of the actual alterations 

 which albumen undergoes in its transforma- 

 tion into peptones, and thinks it possible that 

 a rearrangement of the atoms takes place ; but 

 he has few supporters. Henninger believes, 

 after a long investigation, with Wurz and 

 Hoppe-Seyler, that the formation of peptones 

 is due to a process of hydration. He has also 

 attempted to produce albumen again from his 

 peptones by a process of dehydration, and has 

 succeeded in forming syntonin, the next modi- 

 fication of albumen. .This result has been con- 

 firmed by Hoffineister, who has, by dehydrating 

 fi brine-peptone and dissolving the product in 

 cold water, obtained a flocculent residue show- 

 ing all the reactions of albumen. Maly holds 

 that there is only one principal product of di- 

 gestion, one peptone, which differs but slightly 

 from the mother- substance in composition. 

 Kossel inclines to the belief that more than 

 one peptone can originate from a single albu- 

 men, and that these bodies which we now term 

 peptones do not actually possess a chemical in- 

 dividuality. As regards the nature of peptone, 

 whether it is an acid or a base, the preponder- 

 ance of evidence is on the side of its being an 

 acid, while it is capable of acting both as an 

 acid and as a base. Henninger regards the 

 peptones as feeble ami do -acids, and, as such, 

 capable of acting either as acids or bases. The 

 combination of peptones with acids is formed 

 directly whenever an acid is added to a solu- 

 tion of peptone, and the compound is a salt of 

 the peptone corresponding to the acid em- 

 ployed. Peptones also combine with salts, 

 forming a very loose union. 



R. H. Chittenden has given an account of an 

 examination for arsenic of a human body dis- 

 interred for the purpose nearly six months after 

 burial, in order to ascertain the actual amount 

 of poison in the whole body, and at the same 

 time to glean all possible facts relative to its 

 distribution. The analysis was performed by 

 oxidizing a weighed amount of the sampled or- 

 ganic matter with nitric and sulphuric acids 

 at elevated temperatures, and ultimately ob- 

 taining the arsenic and weighing it in the 

 metallic state, the results being verified when 

 possible by duplicate analyses. From the 

 amount of arsenic found in the portion exam- 

 ined, the content of the entire organ or por- 

 tion of tissue was calculated. By this method, 

 the internal organs were found to contain 

 1'1694 grain of arsenious oxide, and the rest 

 of the body 1-9498, making a total of 3'1192 



