950 EDITORIALS. 
of potassium, of calcium, and of ammonium, lactate of calcium, phos- 
phates of calcium and of magnesium, sulphates of calcium and of 
iron, and chloride of sodium. When water and tartaric acid were 
added to this mixture, as directed, and the whole examined under 
the microscope, a very interesting and often complex series of cur- 
rents were seen, both on the surface and within the mass. The 
currents would stream past one another in opposite directions, often 
reverse, and flow in new directions, and particles of the mingled 
substances in the soapy mass were often borne along in the current. 
This would continue from fifteen minutes to half an hour. But 
these movements were of the more fluid mixture of water and 
the soluble ingredients, and not of the substance of the mass. 
No protrusions of the nature of pseudopodia were seen, nor was 
there anything in the structure or activities of this substance that is 
truly characteristic of really living protoplasm. Professor Herrera 
states in his letter, however, that on one occasion when observing 
a drop of the “synthetic protoplasm” floating upon oil, he saw the 
production of a pseudopodium-like structure with a clear peripheral 
layer. 
He also calls attention to the fact that oxygen is necessary for the 
vital processes, and suggests the interesting hypothesis that as the 
currents in the synthetic protoplasm are kept up by the liberation of 
carbon dioxide, the protoplasmic movements observed in animals and 
plants may be due to a similar process. This may be a suggestion 
in the right direction, but we think most naturalists will agree that 
this cannot go very far toward explaining the extremely complex 
activities of the living substance. 
