No. 1.] ORIGIN OF HUMAN MONSTERS. 390 
hundred pregnancies, as my tables indicate, we then have one 
foetus with spina bifida in 1,000 pregnancies, which is also 
Koch’s? proportion. In other words, five young embryos 
with spina bifida are aborted early, while one goes on to full 
term or may live after birth. 
The smallest embryo with spina bifida in my collection is 
2.1 mm. long and in general appears normal. However, the 
brain is atrophic, is quite wide open and may be considered 
anencephalic. The cord below is also wide open, wider than 
in other embryos of this age which have been described. A 
similar but a little larger embryo has been described by Tor- 
neau and Martin (Fig 1, Plate I). Their embryo is 8 mm. 
long, apparently normal in form, with the spinal cord below 
wide open. Sections of the specimen showed that the spinal 
ganglia are present, lying on either side of the motor roots, 
which nearly encircled the chorda. There is also some 
histolysis of the cord. No. 189 is a case of complete spina 
bifida with marked histolysis and destruction of the superior 
end of the central nervous system. 
The other specimens given in the footnote on page 27 
show a variety of forms of spina bifida of the cord, probably 
the most interesting being No. 293, in which there is histolysis 
of the membrana reunions behind. A specimen like this may 
represent an early stage of spina bifida occulta. Otherwise 
the remaining specimens show a considerable destruction of 
tissues, both mesodermal and nervous, which makes them cor- 
respond more with the cases found at birth. Here the nervous 
tissue is quite vascular, often forming peculiar tissues, such 
as Von Recklinghausen? has pictured. 
Recently Voigt?! has described a case of cervical spina 
bifida in an embryo 18 mm. long, which was aborted fifty- 
four days after the last menstrual period. A much more satis- 
factory account of several specimens is given by Fischel’? in 
°*Koch, Beitrage zur Lehre von Spina Bifida, Kassel, 1881. 
Von Recklinghausen, Virch. Archiv, 105. 
“Voigt, Anatom. Hefte, XXX, 1906. 
“Fischel, Ziegler’s Beitrage, XLI, 1907. 
