In his germ-layer theory Remak's standpoint is histological rather than morphological. The distinction which he draws between the sensory and trophic layers on the one hand, and the motor-germinative layer on the other, is entirely a histological one. The greater part of his book, indeed, is devoted to a study of the histogenesis of the different organs of the body; he is bent chiefly upon unravelling the part which each germ-layer takes in the formation of each tissue and organ.
His generalisation that two of the germ-layers give rise exclusively or almost exclusively to one kind of tissue excited great interest at the time, and gave the direction to histogenetic research for quite a number of years, though in the end it turned out to be insufficiently founded.
Though Remak's germ-layer theory had thus principally a histological orientation, it laid down the main lines of the modern morphological treatment of the germ-layers.
[293] Embryologie des Salmones, 1842.
[294] Die Cellularpathologie in ihrer Begründung auf physiologische und pathologische Gewebelehre, Berlin, 2nd ed. 1859; Eng. trans., by Chance, 1860.
[295] Arch. path. Anat. Phys., vii., pp. 1-39 (1854).
[296] Bericht über die Fortschritte der mikroskopischen Anatomie im jahre 1854. Müller's Archiv, 1855. See also 1856.
[297] Hndb. d. Physiol., i., 1835.
[298] See Leuckart's reply to Ludwig's criticism, in Zeit. f. wiss. Zool., ii., p. 271, 1850.
[299] Leipzig, 1853.