IRON COMPOUNDS IN ANIMAL AND VEGETABLE CELLS. 271 
the occurrence of such, and it is scarcely possible to explain 
away the objection without advancing some hypotheses regard- 
ing the action of the sulphur and the phosphorus in the 
nuclein. I propose to detail these on another occasion. 
EXPLANATION OF PLATES 10—12, 
Illustrating Dr. A. B. Macallum’s paper “On the Distribution 
of Assimilated Iron Compounds, other than Hemoglobin 
and Hematins, in Animal and Vegetable Cells,” 
EXPLANATION OF FIGURES. 
Note.—In the preparation of all the figures Abbé’s camera lucida was em- 
ployed when the size of the objects represented permitted its use, and all 
except 25, 26, 35, and 36 are illustrated as they were seen with an apocbro- 
matic immersion objective (Zeiss 8 mm., 2 mm., or 15 mm.). The excep- 
tions are represented as they appeared under a Zeiss D. Figs. 1—40 show 
the distribution of assimilated iron as it was demonstrated by the dark green 
colour of ferrous sulphide, but in Figs. 41—53 the disposition of iron com- 
pounds of this kind is indicated by the colour of the Prussian blue reaction. 
Fic. 1.—A nucleus and a cell from the testicle of Necturus lateralis. 
Alcohol, the glycerine and sulphide mixture eleven days. x 620. This and 
the two succeeding illustrations were drawn from the very first preparations 
made with this reagent. 
Fie. 2.—Testicular elements of another example of N. lateralis. Alcohol, 
the glycerine and sulphide mixture eleven days. x 620. 
Fic. 3.—a, a leucocyte, 4, a red corpuscle, of N. lateralis. Alcohol, the 
elycerine and sulphide mixture six days. x 500. 
Fie. 4.—Two yeast-cells, Saccharomyces cerevisiz. Alcohol, the 
glycerine and sulphide mixture ten days. x 1500, 
Fic. 5.—Four yeast-cells, Saccharomyces Ludwigii. Alcohol, the 
glycerine and sulphide mixture four days. x 1640. 
Fie. 6.—The developing and fully-formed spores of Cystopus candidus. 
a, b, c, d, e, alcohol, sulphuric acid alcohol two days, ammonium hydrogen 
sulphide in glycerine. x 750. /, alcohol, the glycerine and sulphide mixture 
ten days. x 680. 
VOL. 388, PART 2.—NEW SER. s 
