1899] AS REGARDS PROTOPLASM 167 
cell it is in reality an alveolar structure —an emulsion — such as 
Biitschli has described. The living stuff of an Echinoderm ovum is 
in the form of a fine emulsion consisting of a continuous substance in 
which are suspended drops of two orders of magnitude and of different 
chemical nature, the larger drops determining the primary alveolar 
structure as described by Biitschli, the smaller drops determining the 
secondary or finer alveolar structure as described by Reinke. As to 
the astral rays in the sea-urchin egg and elsewhere, they involve a 
radial arrangement of the alveoli, but they involve more, namely, 
definite fibrillae which grow by progressive differentiation out of the 
general cytoplasmic meshwork. 
The phrasing of the last sentence suggests a more general con- 
clusion —“ that alveolar, granular, fibrillar, and reticular structures 
are all of secondary origin and importance, and that the ultimate 
background of protoplasinic activity is the sensibly homogeneous matrix 
or continuous substance in which those structures appear.’ Not that 
the author puts his finger upon this, so to speak, and says this is the 
living matter, for “in its fullest meaning the word living implies the 
existence of a group of co-operating factors more complex than those 
manifested by any one substance or structural element in the cell, 
nevertheless, we are perhaps justified in maintaining that the continuous 
substance is the most constant and active element, and that which 
forms the fundamental basis of the system, transforming itself into 
granules, drops, fibrillae or networks in accordance with varying 
physiological needs.” Thus we are led to the conclusion that the 
physical basis of life is in the invisible organisation of a substance 
which seems to the eye homogeneous. Beyond this, as far as 
morphological aspects are concerned, all is hypothesis, and the form 
of hypothesis which Professor Wilson favours is “that the homogeneous 
or continuous substance may be composed of ultra-microscopical bodies, 
by the growth and differentiation of which the visible elements arise, 
and which differ among themselves chemically and otherwise, as is the 
ease with the larger masses to which they give rise.” 

The Darmstadt Museum. 
ALTHOUGH the new building of the Grossherzogliche Museum at 
Darmstadt is unfinished and untenanted, the plan of the zoological 
portion has been carefully worked out by Dr. G. von Koch, the director, 
and some idea of its main features can be gained from his programme 
and from the newer cases in the old museum. 
In the “ Schausammlung” or show collection intended for general 
instruction, there is of course a systematic series, but prominence is 
given to cases showing things more or less as they are in nature or 
