286 On the Presence of Iron in Chromatin. 



mine the presence of iron in the chromatin of a large number of 

 vegetable cells. 



I asked Mr. J. J. MacKenzie to undertake the study of the distri- 

 bution of iron in fungi and alga&, and very encouraging have been, 

 so far, the results of his examination. He has found, for example, 

 that in the gonidia of Cystopus candidus, hardened in alcohol, the 

 application of warm ammonium sulphide and glycerine on the slide 

 for eight days brings out the presence of four or more blue-green, 

 round bodies, measuring !'(>/* in diameter, and corresponding to the 

 nuclei of the zoogonidia, the rest of the protoplasm of the gonidia 

 Remaining absolutely uncoloured. The coloured parts gave one the 

 impression as if the gonidia had been given a purely nuclear stain 

 with iodine-green. Mr. MacKenzie has also observed interesting 

 results following the employment of ammonium sulphide on some 

 blue-green algae, which indicate that here also, there is a substance 

 likfi chromatin in firm combination with iron. 



I think that enough has been advanced to show that my view, that 

 the chromatin of every cell, animal and vegetable, is an iron-holding 

 compound, is one which is now capable of proof. I cannot assert 

 that it is proved as yet, since I am aware that that can only be done 

 after an extensive series of observations made and careful work 

 performed. Mr. MacKenzie, Mr. Bensley, and myself are continuing 

 the investigations outlined, and we hope before long to be in a 

 position to bring forward an abundance of interesting facts, which 

 are now accumulating, and of which those given here are examples. 



I forego any speculation as to the bearings which my observations 

 may have on our knowledge of animal and vegetable metabolism. I 

 content myself here with referring briefly to the condition in which 

 the iron is present in the chromatin. As stated already, I have 

 found that the haemoglobin of Amphibia is formed from the chromatin 

 of the haematoblasts. This would seem to indicate that the iron is 

 attached in the chromatin molecule to an atom-group somewhat like 

 that of haematin. As the oxygen-carrying property of haemoglobin 

 is generally attributed to the presence of the iron in it, we may ask 

 ourselves whether the chemical processes in the chromatin of the 

 living cell are due to a constant alternation of the oxidised and 

 reduced conditions of the iron in the chromatin molecule. As haemo- 

 globin results from degeneration or disintegration of chromatin, we 

 would naturally expect to find in it one or other condition specially 

 prominent. The more stable condition is that of oxidation. It is 

 possible that in living chromatin the conditions are more readily 

 interchangeable, and that therein lies a basis for a theory of those 

 chemical processes of the cell which are grouped under the term 

 "vital." 



