BIRTH AND AFFINITIES OF CRYSTALS 133 
of the new material. This happens with the alums, as mentioned 
above. 
The researches which I have described in this paper give us, 
I think, some insight into the invisible structure of the crystal 
edifice and its manner of growth; they also lead to one other 
inquiry which has not yet been carried out. Parallel growths 
take place upon crystals of the same substance ; they also take 
place upon crystals of another substance having the same 
structure and molecular volume. A crystal of the dissolved 
substance dropped into a metastable solution at once relieves 
the supersaturation and continues to grow. Is it the case 
that the supersaturation can also be relieved by a crystal of some 
other substance, provided that it has the same structure and 
molecular volume? I think that this will probably be estab- 
lished by future experiments, for I have found that the super- 
saturation of a metastable solution of sodium nitrate appears 
to be relieved by calcite, but not by the other members of the 
calcite group. 
If this be so, the relief of supersaturation and the parallel 
growth are two occurrences which can hardly be referred 
merely to the geometrical fitting together of two structures, 
for this could scarcely force the dissolved substance out of 
solution. I would rather think of a crystal as an assemblage 
of vibrating particles, and of the geometrical structure as the 
expression of some rhythmical motion with which they are 
endued, so that two crystals which have similar structures are 
in tune with each other, and respond each to the other’s palpi- 
tations. Is it not possible that the irregular motions of the 
liquid substance in solution may respond to the rhythmical 
motion of the crystal particles of a kindred substance in tune 
with it introduced into the solution, just as one violin responds 
to another, and so may be transformed into the regular pulsa- 
tions which perhaps accompany the building up of a crystalline 
structure ? 
BIBLIOGRAPHY 
Miers, H. A., Address to the Geological Section of the British Association, 1905, 
Report, p. 388. 
MACALLUM, A. B., and MENTEN, Miss M. L., On the Distribution of Chlorides in 
Nerve Cells and Fibres, Proc. Roy. Soc., 1906, 77B, p. 165. 
Miers, H. A., and ISAAC, FLORENCE, The Refractive Indices of Crystallising 
Solutions, with especial reference to the Passage from the Metastable to the 
Labile Condition, Journ. Chem. Soc., 1906, 89, p. 413. 
