IS93.J 91 [Hyatt. 
remain true to the stock in their strictly morpliic lines of modifica- 
tion as hjiig as they do not Ijecome ])arasitic, tliat is, as long as 
they remain subject to the similar surroundings of the external 
world. In this paper the exceptions due to parasitism and all 
other facts than those bearing on the suitability of the term to be 
employed to designate the researches which deal with the correla- 
tions of ontogeny and phjdogeny, are left out of consideration. 
Heredity is obviously manifested entirely in the results of 
gi'owth and appears chiefly in the cytoplasmic structures which 
Dr. Minot so clearly places before us as constantly increasing 
with age while the comparative size of the nucleus, which repre- 
sents the power of growth force, decreases. Whether this be 
granted or not, it can hardly be denied that, in describing the 
development of organisms along phylogenetic lines, we are deal- 
ing with cycles of progression and retrogression which are quite 
distinct from the growth of the body as determined by the law 
that governs its increase or reduction in bulk, and that one cannot 
describe the study of both series of phenomena under the same 
general term without danger of confusion. 
I have several times used the term morphogenesis in a inore 
descriptive sense than that in which it has been used by Haeckel. 
This philosophic thinker and naturalist divides morphology into 
anatomy and morphogeny, and uses morphogeny in nearly the 
same sense as the ])roposed term bioplastology, including under it 
ontogeny (or embryology) and ])hylogeny (or paleontology). 
Subsequent parts of his text show that he really means by onto- 
geny^ the entire life of the individual and all its transformations, 
and by phylogeny the entire history of the evolution of the phy- 
lum. The use of j^aleontology as a co-extensive with phylogeny 
is obviously wrong, since pliylogeny, meaning thereby the evolu- 
tion of the phylum, is perhaps better studied by means of fossil 
remains, but it reaches into recent times, and should include living 
animals as well as all of their fossil remains. This somewhat 
obscures this great discoverer's meaning, but there can be no 
doubt that he used both ontogeny and phylogeny in tlieir widest 
application and understood the i)henomena in their more general 
and physiological correlations. 
1 The researches of Maupas do not contradict this statement since his successive 
{fenerations of Infusoriae, although completing a cycle, are plainly (as pointed out by 
himself) ontogenic when compared with the ontogenic cycles of the Metazoa. 
