III.] LIFE AND DEATH. 127 



other artificial means, and would not the state which followed 

 be death ? Even if we define death as an arrest of life, the dis- 

 solution of Magosphaera into many single cells which still live, 

 is not death, for life does not cease in the organic matter of 

 which the sphere was composed, but expresses itself in another 

 form. It is mere sophistry to say that life ceases because the 

 cells are no longer combined into a colony. Life does not in 

 truth cease for a moment. Nothing concrete dies in the disso- 

 lution of Magosphaera ; there is no death of a cell-colony, but 

 only of a conception. The Homoplastides, that is cell-colonies 

 built up of equal cells, have not yet gained any natural death, 

 because each of their cells is, at the same time, a somatic as 

 well as a reproductive cell : and they cannot be subject to 

 natural death, or the species would become extinct. 



It is more to the purpose that Gotte has sought for an illus- 

 tration of death among those remarkable parasites, the Ortho- 

 nectides, because in them we do at any rate meet with real 

 death. They are indeed very low organisms ; but nevertheless 

 they stand far above Magosphaera, even if the latter were hypo- 

 thetically perfected up to the level of a true Homoplastid, for 

 the cells which compose the body of the Orthonectides are not 

 all similar, but are so far differentiated that they are even 

 arranged in the primitive germ-layers, and a form results which 

 has rightly been compared with that of the Gastrula. It is true 

 they are not quite so simple as Gotte ^ figures them, for they 

 not only consist of ectoderm and germ-cells, but, according to 

 Julin ^, the endoderm is arranged in two layers — the germ-cells 

 and a layer which forms during development a strong muscular 

 coat ; and in the second female form the egg-cells are sur- 

 rounded by a tolerably thick granular tissue. There is never- 

 theless no doubt that in the first female form, when sexually 

 mature, the greater part, not only of the endoderm but of the 

 whole body, is made up of ova, so that the animal resembles 

 a thin-walled sac full of eggs. The ova escape by the bursting 

 of the thin ectoderm, and when they have all escaped, the thin 

 disintegrated membrane, composed of ciliated cells, is no 

 longer in a condition to live, and dies at once. This is the 



1 1. c, p. 42. 



2 ' Contributions a Thistoire des Mesozoaires. Recherches sur 1 or- 

 ganisation et le developpement embryonnaire des Orthonectides,' Arch, 

 de Biologic, vol. iii. 1882. 



