1895.] Iron Compounds in Animal and Vegetable Cells. 



III. " On the Distribution of Assimilated Iron Compounds, 

 other than Haemoglobin and Hasmatins, in Animal and 

 Vegetable Cells. Preliminary Communication." By A. B. 

 MACALLUM, Associate-Professor of Physiology, University 

 of Toronto. Communicated by Professor M. FOSTER., Sec. 

 R.S. Received December 3, 1894. 



The question of the presence of iron in the chromatin of animal 

 *md vegetable cells and the methods of demonstrating the element in 

 this substance were discussed in a communication to the Royal 

 Society made more than three years ago.* Since then I have 

 endeavoured to determine with perfected methods the distribution of 

 assimilated iron compounds in cells of all classes, and have succeeded 

 in obtaining results of which the present communication is an ex- 

 ceedingly condensed and preliminary account. A fall account will 

 be published elsewhere. 



The methods adopted were such as prevented a confusion of the 

 iron of inorganic and albuminate combinations with that of as- 

 similated compounds. The reagent which proved to be of the 

 greatest service was freshly prepared ammonium hydrogen sulphide 

 made from a solution of ammonia of 0'96 specific gravity, and 

 applied, mixed with glycerine, to the isolated cells in the way 

 already described. Sulphuric, hydrochloric, and nitric acids, dis- 

 solved in certain proportions in alcohol of 95 per cent, strength, 

 have been found to liberate the iron of assimilated compounds, but 

 the results obtained with these acids were, in all cases where this 

 was possible, controlled by experiments with the sulphide reagent. 

 The iron liberated was readily demonstrated in the form of ferrous 

 sulphide or of the Prussian-blue compound. 



The fact that the iron of coagulated haemoglobin is unaffected by 

 ammonium hydrogen sulphide enables one to overcome the diffi- 

 culties presented by the presence of that colouring matter in many 

 animal forms. The iron of haematin is, however, liberated by that 

 reagent, but the rapidity with which this is done, under the most 

 ordinary conditions, may be employed to distinguish the iron so 

 derived from that of other organic compounds. Whether chlorophyll 

 contains iron as a constituent of its molecule is still a matter of dispute, 

 but the presence of that colouring matter in vegetable cells does not 

 complicate the results, since in the hardening processes, especially 

 when alcohol is used, it may be wholly removed from vegetable tissues, 

 which then, so far as the distribution of " masked " iron is con- 



* " On the Demonstration of the Presence of Iron in Chromatin by Micro- 

 chemical Methods," Koy. Soc. Proc.,' vol. 50, p. 277. 



