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addition alkaline annelids artificial membrane formation artificial parthenogenesis Asterias astrospheres blastomeres blastula blood brane brane formation butyric acid c.c. of sea-water cause membrane formation cell division centrosomes chemical chorion concentration cortical layer cytolysis cytolytic develop into larvae diffuse disintegration effect eggs developed eggs form eggs of Arbacia eggs of purpuratus eggs remain eggs to develop embryo Entwicklungsmechanik experiments fact fatty acid female fertilization membrane fertilized with sperm flasks form membranes Hence hydroxylions hyper hypertonic solution increase induced Jour lack of oxygen Lottia lysins maturation ment minutes NaCl NaOH NH4OH normal sea-water nucleus observed osmotic pressure oxygen permeability Physiol plutei polar bodies potassium cyanide produced rate of oxidations saponin sea-water 50 c.c. segmentation species spermatozoon SrCl2 stage starfish starfish eggs Strongylocentrotus substance surface temperature tion tonic solution transferred to normal treated treatment Ueber unfertilized eggs unfertilized sea-urchin egg writer Zeitschr
Page ii - THE CAMBRIDGE UNIVERSITY PRESS LONDON AND EDINBURGH THE MARUZEN-KABUSHIKI-KAISHA TOKYO, OSAKA, KYOTO KARL W. HIERSEMANN LEIPZIG THE BAKER & TAYLOR COMPANY NEW...
Page 91 - Those eggs that had been in the hypertonic sea-water with air were all completely disintegrated by " black cytolysis." Ten per cent. of the eggs had been transformed into "shadows" (white cytolysis). It goes without saying that all the eggs that had been in the aerated hypertonic sea-water five and a half hours were also dead. The eggs that had been in the same solution in the absence of oxygen appeared all normal when they were taken out of the solution, and three hours later — the temperature...
Page 35 - ... difference between those in alkaline solutions and those in sea-water. He suggested that by this time- the alkali was largely neutralized by the acids produced in the process of growth. Later, in his "Artificial Parthenogenesis and Fertilization" he takes an entirely different position. He says that "he has since vainly attempted to show that the rate of development of the sea-urchin egg can be increased with the increase of the concentration of hydroxylions in the sea-water. This leads him to...
Page 91 - ... they were all. without exception in a perfectly normal two- or four-cell stage. The further development was also in most cases normal. They swam as larvae at the surface of the vessel and went on the third day (at the right time) into a perfectly normal pluteus stage, after which their observation was discontinued. Of the eggs that had been five and a half hours in the hypertonic sea-water deprived of oxygen, about 90 per cent, segmented. Let us consider one more illustration from Loeb's work...
Page ii - This new work presents the first complete treatment of the subject of artificial parthenogenesis in English. Professor Loeb published four years ago a book in German under the title Die chemische Entwicklungserregung des tierischen Eies.
Page 209 - Now it appears to me (so far as the osmotic properties of the membrane are concerned) that this formation of droplets depends upon the fact that a colloidal substance, which lies below the surface layer of the unfertilized egg or is secreted from the egg, suddenly swells by absorption of sea-water.
Page 121 - ... the strengthening of the green line in the spectrum and the weakening of the yellow lines. With this stronger field there is also a large increase in the conductivity of the vapor, which is no doubt due to ionization in this region. The change in the relative intensity of the lines can be explained on the assumption that it is due to the formation of a greater number of those positive ions which lack two or more electrons. NOTE ON THE CONSTRUCTION OF THERMOPILES.1 BY WW COBLENTZ. WITHIN the past...
Page 294 - ... through artificial parthenogenesis. These latter experiments have shown that the spermatozoon does not cause the development by carrying an enzyme or katalyzer into the egg, which the latter needs in order to develop, but causes the development by altering the surface layer of the egg. If the development of the egg were caused by an enzyme carried into the egg by a spermatozoon, the rate of cleavage of slowly developing eggs should be accelerated by a spermatozoon of a species developing at a...
Page 297 - ... heteroclitus fertilized on the same date were already hatching. The hybrid embryos had formed the pigment characteristic for the pure breed of Fundulus heteroclitus. But the anomalies of the embryos are very obvious. The embryos are rather small, owing to the slowness with which they digest the yolk. Their eyes are abnormal and approach the cyclopean condition. In many specimens only irregular masses of pigment indicate where the eyes should be. The head is comparatively small and not bent as...
Page 294 - ... of sterilizing the pipettes by boiling them after each experiment, instead of sterilizing them by rinsing in distilled or fresh water as is often done. 3. Moenkhaus measured the rate of segmentation in hybrid fish eggs and found that the rate for the first five cleavages is determined by the egg.4 The egg of Ctenolabrus segments about forty minutes after impregnation with sperm of its own kind, while the egg of Batrachus tau, if fertilized with the sperm of the same species, segments after about...