The Iron Content of the Human Brain.—II
1. The content of various forms of iron in different parts of the human brain is recorded, including water-soluble alcohol-ether insoluble iron, alcohol-ether soluble iron, iron combined with protein and iron due to blood.

2. Further results confirmatory to the previous paper (1) are given, showing that there is an excess of “available” or non-haematin iron in those G.P.I. cortexes having a histo-chemical deposit of iron.

3. The results indicate that the excess referred to is in the non-protein iron fraction.

4. The large excess of total iron in the pallidus and corpus striatum is, in the latter case, due largely to protein iron, but in the former case also to the iron in the alcohol-ether extract.

5. The cortex and white matter each contain about 70% protein iron, although the percentage of protein is 47 and 27 respectively (4).

6. The water-soluble alcohol-ether insoluble iron constitutes about 12% of the iron in the white matter, and 25% of the iron in the cortex, corpus striatum and pallidus.