Journal of 



Applied Microscopy 



and 



Laboratory Methods 



Volume V. JANUARY, 1902. Number 1. 



Artificial Imitations of Protoplasmic Activities, and 

 Methods of Demonstrating Them. 



Activities of the same character as many of those shown by some of the 

 lower organisms, such as Amoeba, may be produced through the action of chemical 

 and physical laws. Experiments demonstrating this fact are valuable for an 

 analysis of the behavior of these creatures, and many of those worked out by 

 recent investigators (notably by Rhumbler) are very easily performed. A prac- 

 tical knowledge of them deserves to be more widespread than seems at present 

 to be the case. The following are some of the experiments which the author is 

 accustomed to demonstrate to classes in biology and general physiology : 



1. Amceboid Movements. Amoeba may be regarded, from a material standpoint, 

 as a chemically active mass of viscid fluid which is continually interchanging- 

 substance with the medium surrounding it. It is constantly taking oxygen and 

 other substances from the water, constantly giving off carbon dioxide and other 

 excreted substances. Could such a mass be reasonably expected to change its 

 form and move about ? We may answer this question experimentally by provid- 

 ing an inorganic drop which fulfills these conditions, and observing it. The 

 simplest and most satisfactory method which the author has found for doing this 

 is to employ a drop of clove oil mounted on an ordinary glass slide in a mixture 

 of three parts glycerin with one part 96 per cent, alcohol, and covered with a 

 cover-glass. The clove oil and alcohol are miscible, so that a little alcohol is 

 continually passing into the drop of clove oil, a little of the clove oil out into the 

 alcohol ; the conditions proposed above are therefore satisfied. The glycerin 

 acts simply as a neutral medium to prevent too rapid interaction of the clove oil 

 and alcohol, and by its thicker consistency to prevent the movements from taking 

 place too rapidly. 



Such a drop of clove oil will change its form, send out " pseudopodia," and 

 creep about much as Amoeba does. At first it may be circular, then a long pro- 

 jection will be sent out on one side, the entire drop may elongate, and progress 

 as a whole in that direction. Currents may be formed within it, " pseudopodia " 



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