ARTIFICIAL PropucTion oF NorMAL Larvae 579 
the concentration is a little higher, the dissolution of the 
nuclear membrane occurs, but the protoplasm on account of 
its rigor is unable to scatter the chromosomes and to seg- 
ment. If such eggs be put back into normal sea-water, the 
protoplasm gradually loses its condition of rigor. The 
motions that lead to the scattering of chromosomes return 
sooner than the ability to segment. In such cases the pro- 
cess probably occurs in the form in which Morgan observed 
it. There may be intermediate stages and variations. 
I mention these experiments mainly for the reason that 
they led Morgan to a very important step, namely, to try the 
effect of an increase in the concentration of sea-water upon 
unfertilized eggs. He found that eggs that were put into 
sea-water whose concentration had been raised by the addi- 
tion of 14 per cent. NaCl or 34 per cent. MgCl, began to 
segment into two or more cells when put back into normal sea- 
water. This segmentation went in some cases about as far as 
the sixty-four-cell stage, but then the development stopped.’ 
Meade made the observation that the unfertilized eggs of 
Cheetopterus could be caused to throw out the polar bodies 
by the addition of a small amount of KCl to sea-water. 
The addition of NaCl had no such effect.” Last year Dr. 
Mathews made an experiment with rennet ferment which he 
did not publish. In a previous paper on the origin of 
fibrinogen he had expressed the idea that the origin of 
the astrospheres in a cell was due to a process of coagu- 
lation. He tried the effect of rennet ferment upon unfer- 
tilized eggs of the sea-urchin to see whether he could in this 
way cause the egg to develop. The eggs were put into a 
solution of rennet tablet and when taken out began to seg- 
ment, but the development did not go beyond the division 
into a comparatively small number of cells. The phenomenon 
17, H. Morean, Archiv fiir Entwickelungsmechanik, Vol. VIII (1899), p. 448, 
2Mxap, Lectures delivered at Woods Hole, 1898 (Boston: Ginn & Co.). 
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