Coralline growths may also be obtained by using appropriate chemical solutions. For this purpose the solution of silicate, carbonate, and dibasic phosphate should be diluted to half strength, with the addition of 2 to 4 per cent. of a concentrated solution of sodium sulphate or potassium nitrate.
Coral-like forms may also be grown from a semi-saturated solution of silicate, carbonate, and dibasic phosphate, to which has been added 4 per cent. of a concentrated solution of sodium sulphate or potassium nitrate. In this we may obtain beautiful growths like madrepores or corals, formed by a central nucleus from which radiate large leaves like the petals of a flower. The presence of nitrate of potassium produces pointed leaves with thorn-like processes recalling the forms of the aloe and the agave.
Most remarkable fungus-like forms may be obtained by commencing the growth in a concentrated solution, and then
carefully pouring a layer of distilled water over the surface of the liquid. The resemblance is so perfect that some of our productions have been taken for fungi even by experts. The
stem of these osmotic fungi is formed of bundles of fine hollow fibres, while the upper surface of the cap is sometimes smooth, and sometimes covered with small scales. The lower surface of the cap shows traces of radiating lamellæ, which are sometimes intersected by concentric layers parallel to the outer
surface of the cap. In this case the lower surface of the cap shows a number of orifices or canals similar to those seen in many varieties of fungus.
