482 
The old Grecian philosophers noted and classified monstrosities in a way. 
Empepoc.ies believed that they were due to too many or too few spermia, 
ARISTOTLE in his Genesis of Mammals, says in regard to the arrest of devel- 
opment and monstrosities, ‘‘The former is only a form of malformation and 
the latter the same with supernumerary parts, i.e., many legs, arms, heads, 
etc. For it is a characteristic of malformations that something is wanting or 
excessive. The malformations belong to those phenomena that are contrary 
to nature, but not to all Nature, but to the usual course of Nature.” Whether 
the monster represents one or more fused, he determines from the central 
organs. DEMOKRITES on the other hand, took the ground that those malformations 
with excess, resulted from contact with spermia at different times. After a 
long unfruitful period malformations appear in the realms of research and 
take part in the battle between exponents of the preformation theory and 
epigenesis. Both sides believed to have support for their theories in this 
condition. Preformatists believed that all or most malformations were preformed 
and that they later occurred through mechanical causes as fusion of regularly 
formed embryos. 
The victory for epigenesis which was the causative advancement of 
Embryology, led C. F. WoLrr! to express the thought that malformations 
could represent the developmental stages of the fetus. He considered the 
cause of malformations to be a deviating or declining activity of the vegeta- 
tive force or power. His conclusions were drawn from the study of a double 
and a triple chick embryo and the several malformed embryos of bony fishes. 
TIEDEMANN ? later expressed the same views. 
MeckEL ® also concurred in the above view and grouped all malformations 
of its variety under the term of “arrested development”. Hatter * after col- 
lecting and studying the literature of preceding malformations believed that 
in all deviations of development there is a law, a return or repetition, but no 
arbitrariness, SÖMMERRING ° was convinced in his observation of monstrosities 
that there was a definite order or arrangement and a definite course and that 
just as in diseases, nature does not play an infinite role. MEcKEL and BLUMEN- 
BACH ® explained all malformations as a deviation of the creative principle. 
MeckEL believed that the individual part or the whole body could seldom be 
duplicated more than once. He distinguished between ordinary duplication 
(fingers, hands, etc.) and what he terms the procreative variety (two incomplete 
bodies fused at points). The latter he believed consisted of two independently 
developed embryos that fused later; the fusion he states is oftenest lateral 
and less often cephalad or caudad. MEcKEL refers to precocious puberty, the 
appearance of hairs, teeth and bone (teratomos?) without a procreative act, 
the occurrence of asexual propagation and to the great ability of regeneration 
shown by many lower animals, as special procreative ability. 
Osam 7 considered a monster that came under his observation as representing 
two separate embryos that lay close together of which one was more poorly — 
nourished than the other. As they lay with their intestines external to the 
abdominal wall, fusions of these organs occurred and the weaker was gradually 
drawn into the abdominal cavity of the stronger as the intestines of the latter 
were drawn into the enlarging cavity. Hurguanp ® takes another view of the 

