272 NATURAL SCIENCE [April 



novel things to say. She has spent long years on the patient study 

 of living protoplasm : she has compared the kaleidoscopic changes in 

 living cells and nuclei with the arrested, possibly distorted, pliases of 

 them seen in fixed and stained preparations. Apparently she has 

 unusual keenness of vision and patience, and has thought no trouble 

 too much did it secure a glimpse into the life of living matter. Had 

 she drawn a great deal more and written a great deal less, knowledge 

 were more surely her debtor. As it is, she has secured many valuable 

 observations. 



In his main idea, Biitschli has found corroboration from Mrs 

 Andrews. Protoplasm is a froth or foam or emulsion. It consists 

 of closely packed bubbles, the contents of which are different from 

 their walls. Mrs Andrews, however, believes that the vesicular 

 structure extends far beyond the limits of Biitschli's observations, 

 and that the visible bubbles grade into series so minute as to appear 

 homogeneous even under the highest possible magnification. More- 

 over, while Biitschli was inclined to attach particular importance 

 to the contents of bubbles, and to regard many of the phenomena of 

 protoplasm as the result of mechanical and chemical relations between 

 the bubble contents and surrounding fluids, Mrs Andrews is more of a 

 vitalist and regards the stuff of the bubble films as the real protoplasm, 

 the active living agent. She describes a large number of cases in 

 which changes of shape, visible under the microscope, cannot be attri- 

 buted solely or even chiefly, after the manner of Biitschli, to chemical 

 changes between the contents of the bubbles and the surrounding 

 media. Those who have watched Biitschli's artificial foams know 

 that when they are brought into a medium different in chemical con- 

 stitution from the contents of the bubbles, osmotic changes are at once 

 set up and these result in curious pseudopodia-like protrusions from 

 the surface of the foam, in streaming movements within its mass and 

 even in movements of translation of the whole mass. Many of these 

 changes are exceedingly similar in appearance to the movements of 

 real protoplasm, and there have been many who have gone beyond 

 Biitschli and roundly declared the causes of the movements of life to 

 be similar in kind to these results of diffusion currents. Mrs Andrews, 

 however, describes many cases in whicli the conspicuous feature of 

 vital movements was actual shifting in position of the continuous 

 substance which forms the walls of the bubbles. She describes that 

 as flowing from phice to place, now thickening the walls of the bubbles 

 in one region, now withdrawing itself into invisible tenuity. More- 

 over, she shows reason to believe that this continuous substance itself 

 may have a foam structure far minuter than anything Biitschli has 

 described. Upon Biitschli's basis, she has increased for us the com- 

 plexity of the conception of protoplasm, and has shown that a large 

 part of living movement may be the result of chemical differences and 

 emulsion currents within the protoplasm. 



Mrs Andrews has made and recorded a specially interesting set 

 of observations on the outer surface of living cells. She declares 

 that in most cases the living matter extends in an attenuated form 

 far beyond what is usually figured and described as its limit. The 

 flickering edge of a cell is usually a net-work of delicate protrusions, 

 ceaselessly changing their position and form. These are in a state of 



