When in 1897 I communicated to the Royal Society a preliminary paper " On the Histology of the Cell Wall with Special Reference to the Mode of Connection of Cells," I hoped that no long period would elapse before the publication of a more detailed account, dealing with “ connecting threads" generally. The pressure of official duties, and to some extent, also, the difficulties of the research, have so militated against my schemes that the full paper still remains unwritten.