lit 
Artificial Protoplasm.’ 
ET it be said at once, for the benefit of the timid, that Professor 
Bitschli does not claim to have made protoplasm. His 
sumptuous quarto contains the results of ten years’ special 
work on the physical side of the phenomena of life. The author is 
very strongly opposed to that school of Biologists who attempt to 
surround the phenomena of life with unnecessary mystery, and who 
clamour at once timidly and virulently against all physical and 
chemical interpretations. He has now been able to make microscopic 
foams which in structure and behaviour, under various conditions, 
marvellously resemble the structure and behaviour of protoplasm. 
These foams have enabled him to bring together the observations of 
himself and others on the actual structure of protoplasm, and to 
furnish a striking theory of its physical nature. 
He tells us that he began his attempts at the making of foams 
with the forlorn feelings of a nineteenth century alchemist. The 
starting point was this: If fine particles of a substance soluble in 
water be mixed with a fatty oil, and the mixture be placed in water, 
the water diffusing into the oil becomes arranged in minute droplets 
round the particles of soluble material, and a foam is formed. 
Owing to the difficulty of breaking up the soluble substance into 
sufficiently minute particles, the particles, viewed under the micro- 
scope, are very coarse. The drops are placed on the under side of a 
coverslip with wax feet, and the coverslip is placed in a drop of water 
on a slide. When such a slide is put ina damp chamber for about 
24 hours, the drop becomes quite milky and opaque. When it is 
flattened out by pressing on the coverslip, or made transparent by 
allowing glycerine to diffuse through it, this drop shows that it is 
composed of a very fine froth. It seems probable that the froth is 
caused by the presence in the oil of a small quantity of soap. 
The soap is more soluble in water, and the solution of soap and 
water has gradually separated out in very fine droplets. Bitschli 
empirically found the best way to produce these froths. Fresh olive 
1 UNTERSUCHUNGEN UEBER MIKROSKOPISCHE SCHAEUME UND DAS PROTOPLASMA. 
By O. Bitschli. (With 6 lithographic tables, and 23 figures in the text.) Leipzig: 
Engelmann, 1892. Price 24 marks, 
