and Laboratory Methods. 1601 



and intelligently adapting means to end to overcome difficulties — qualities which 

 we are accustomed to consider as characteristic of minds in a high degree of 

 development ? 



It will be well in this case as in others to test inorganic fluids before decid- 

 ing what is to be thought of this matter. Suppose we present a similar problem 

 to our chloroform drop ; how will it meet the situation ? 



We may try the experiment as before, with a drop of chloroform at the bot- 

 tom of a watch-glass of water. As the chloroform drop accepts hard shellac, we 

 may present it with a bit of shellac drawn out into a long, fine thread, of length 

 many times the diameter of the chloroform drop. 



The chloroform envelops the filament in some portion of its length, just as 

 Amoeba did. Then it stretches out in both directions along the thread, exactly 

 as was done by Amoeba. (This is most striking when a drop of chloroform 

 floating on the surface of the water is used, though the experiment is otherwise 

 much more difficult to perform under these circumstances.) Thereupon the 

 thread bends, exactly as with Amoeba. The process now continues, precisely 

 parallel with what occurs in the case of Amoeba and the alga thread, until the 

 shellac thread is coiled up within the choloroform drop, like a filament of 

 Oscillaria within an Amoeba. 



This experiment is likewise due to Rhumbler. It is very easily performed ; 

 the following hints will be useful in doing so : 



A drop of chloroform is placed with the medicine dropper on the bottom of 

 a watch-glass full of water. The thread of shellac is obtained as follows : 

 Two pieces of hard gum shellac are held with tweezers, one in each hand. The 

 two are brought in contact, over a flame. The shellac is melted, so that the two 

 pieces stick together. Now, by rapidly drawing them apart, fine threads, becom- 

 ing hard at once, will be obtained. This operation will require some practice 

 before it is done successfully. 



The threads should be excessively fine, almost gossamer like, for the most 

 striking results. Thick threads are wound up only very slowly. 



In performing the experiment, it is important to bring the entire length of the 

 thread completely beneath the surface of the water before letting it come in con- 

 tact with the chloroform drop. If one end is allowed to project above the water, 

 the surface film of the water resists the attempt of the chloroform drop to pull 

 the thread down, so that no clear result will be obtained. Also, be very careful 

 that there are no other minute drops of chloroform in the bottom of the watch- 

 glass, as, if one of these comes in contact with the thread, it will pull the latter 

 in the opposite direction from the main drop, and neither will succeed in rolling 

 it up. The thread should lie freely in the w^ater, in contact with nothing but the 

 one drop of chloroform, if the best results are to be obtained. When the condi- 

 tions are properly fulfilled, the experiment is a very striking one. 



5. Formation of " Artificial Difflugia Shells'' As is well known, Difflugia, 

 one of the close relatives of Amoeba, lives in a shell formed of sand grains, 

 diatom shells, and other small particles cemented together. These particles are 

 fitted together accurately in a single layer, so that no crevices can be discovered. 

 How are these delicate houses built? It would seem that the process must 



