1. Although nucleic acid could not be extracted from Nostoc, all of its constituent radicles, viz. phosphate, pentose, adenine, guanine, cytosine and uracil, were extracted in quantities sufficient to allow of identification.
2. This supports the view that chromatin, a substance of nucleo-protein nature, occurs in the cyanophycean cell, which contains no definite nucleus.
3. The writer suggests tentatively that in the absence of a highly organised nucleus delimited by a membrane, the nuclear materials may more readily diffuse out of the cell and exert a growth-promoting effect on neighbouring plants. This suggestion is supported by the fact that other enucleate organisms, as Saccharomyces and Azotobacter, which contain nucleic acid or its derivatives, show a marked growth-promoting effect on the green plant.