He and others also suggested the applicability of the method to the inter-communication of ships at sea.
It is also urged against these definitions that they are not of universal applicability; that there are exceptional structures which cannot be brought within the limits of any one of them.
That some of the later work on insect embryology has justified the It is now ascertained that the procephalic lobes consist of three growing scepticism in the universal applicability of the " germ-layer divisions, so that the head must certainly be formed from at least theory."
Dumas went no further that thus epitomizing his observations; and the next development was made in 1836 by Auguste Laurent, who, having amplified and discussed the applicability of Dumas' views, promulgated his Nucleus Theory, which assumed the existence of " original nuclei or radicals " (radicaux or noyaux fondamentaux) composed of carbon and hydrogen, and " derived nuclei " (radicaux or noyaux derives) formed from the original nuclei by the substitution of hydrogen or the addition of other elements, and having properties closely related to the primary nuclei.
The applicability of the process has been examined by F.