580 STUDIES IN GENERAL PHYSIOLOGY 
resembled the one described by Morgan to such an extent 
that Mathews came to the conclusion that it was not the ren- 
net which acted in his experiments, but the salts in the ren- 
net tablets. In other words, it was practically the increase 
in the concentration of the sea-water which brought about 
the segmentation of the unfertilized egg, Just as in Mor- 
gan’s experiment. 
There are some earlier observations concerning the fact that 
unfertilized eggs may show the beginnings of segmentation. 
Hertwig mentions,’ that the eggs of Arthropods, Echino- 
derms, and Annelids show a beginning of segmentation 
when left in sea-water for a long time (about twenty 
hours). Tichomirof is quoted as having produced arti- 
ficially a beginning of development in the eggs of Bombyx. 
But these eggs are naturally parthenogenetic. Nussbaum’ 
has repeated these experiments, and, as far as I can see, the 
unfertilized eggs of Bombyx seem to develop naturally just 
as well as with the treatment given them by Tichomirof, 
There is a statement by Dewitz’® that treatment with cor- 
rosive sublimate causes the eggs of a frog to show a begin- 
ning of segmentation, but, if, 1 am not mistaken, Dewitz 
made no sections through these eggs, and he himself ex- 
pressed his doubts to me as to whether there was a real 
segmentation, or whether the surface of the egg simply 
resembled that of segmented eggs. 
Kulagin recently made the following statement: “I ex- 
posed unfertilized eggs of fish and amphibians to diphtheria 
antitoxin, and noticed in many the process of segmentation.” * 
As this one sentence is all he has published about his ex- 
periments, it is impossible to express an opinion concerning 
them. If there was a real segmentation, it still remains an 
10. Hertwic, Die Zelle und die Gewebe, Vol. I, p. 239. 
2M. NussBaum, Archiv fiir mikroskopische Anatomie, Vol. LIII (1899), p. 444. 
3 J. Dewrrz, Biologisches Centralblatt, Vol. VII (1887), p. 93. 
4 KULAGIN, Zoologischer Anzeiger, Vol. XXI (1898), p. 653. 
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