i LIVING MATTEE 39 



Immense progress has been made of late years in the know- 

 ledge of the finer morphological structure of the cell, which 

 must help in determining the chemical differences between the 

 protoplasm and the nucleus, respectively. The first advances in 

 this direction are due to the methods of Micro-Chemistry. 



Kossel's work (1891) has shown that in the nucleus, compounds 

 of protein with substances containing phosphorus largely pre- 

 dominate, while the cytoplasm consists principally of simple 

 proteins and their compounds with combinations which contain 

 no phosphorus. Miescher had previously demonstrated (1874) 

 that the nucleins which he discovered resist the digestive action of 

 gastric juice, and that on placing cells of various kinds in this 

 juice the cytoplasm of the cell dissolves, while the nuclei remain, 

 although of smaller size. Malfatti (1892) next showed that it is 

 the chromatic substance and the nucleolus of the nuclei which do not 

 digest, while the nuclear fluid and a-chromatic substance dissolve. 

 This proves the chromatic substance and the nucleolus of the nuclei 

 to consist essentially of nucleins or their combinations, while the 

 cell protoplasm consists of other proteins. Lastly, Lilienfeld and 

 Monti (1892) showed that ammonium molybdate is a micro- 

 chemical reagent for phosphorus -containing substances, in the 

 presence of which phospho-molybdic acid is formed, which stains 

 brown on the addition of pyrogallol. By means of this reagent 

 it has been ascertained that the compounds of phosphorus, in the 

 most dissimilar cells, are almost exclusively contained in the 

 nucleus. 1 



Carbohydrates and fats, on the other hand, are almost ex- 

 clusively localised in the cytoplasm and limiting cell membrane. 



Nothing is known in regard to the localisation of the inorganic 

 compounds; except that, according to Vahlen, potassium compounds 

 are absent from the nuclei of cells. 



BIBLIOGRAPHY 



F. HOPPE-SEYLER. Physiologische Cheniie, I. Teil, Allg. Biol. Berlin, 1877. 



0. HERTWIG. Die Zelle u. die Gewebe. Jena, 1893-1898. (English translation, 

 The Cell, Campbell, 1895.) 



M. VERWORN. Allgemeine Physiologic. 4th ed. Jena, 1906. (English transla- 

 tion, General Physiology, by F. S. Lee. Macmillan, 1899.) 



R. NEUMEISTER. Lehrbuch d. physiologischen Cheniie. Jena, 2nd ed., 1892. 



F. BOTTAZZI. Trattato di chimiea fisiologica. Milan, 1898. 



0. HAMMARSTEN. Lehrbuch d. physiologischen Cheniie. Wiesbaden, 6th ed., 

 1907. 



E. ABDEUHALDEN. Lehrbuch d. physiologischen Chemie. Berlin and Vienna, 

 1906. 



E. FISCHER. Untersuchungen iiber Amino-sauren, Polypeptide, n. Proteiue. 

 Berlin, 1896. 



1 Scott has shown that it is only the inorganic phosphates which react with 

 this reagent. Organic phosphorus compounds do not react, especially those of the 

 nuclein type, which are not readily hydrolysed into phosphoric acid. PLIMMEII and 

 SCOTT. 



