270 J X FLA MM ATIOX, REGEyERATIOy, GROWTH 



it is soon dissolved. Even more strikingly like phagocytosis and in- 

 tracellular digestion, however, is the result of a similar experiment 

 Avith a piece of glass covered with shellac; the chloroform "ameba" 

 takes it up as readily as it does the shellac alone, but after all the coat- 

 ing is dissolved aAvay the piece of glass is then cast out of the drop. 

 The resemblance to the engulfing, digestion, and excreting of indigesti- 

 ble particles of bacteria, etc., by amebic, is so striking that it seems 

 impossible that there can be any fundamental differences in the two 

 processes. It will also be noticed that the drop takes in only what 

 it can dissolve and rejects what it cannot. 



One of the most remarkable actions of the ameba^, which seems al- 

 most certainly the result of voluntary action, is this: Oftentimes in 

 feeding, an ameba gets hold of a suitable material which is in the 

 form of a long thread, much too long for the ameba to surround. It 

 then proceeds to coil up the thread within its body, by stretching a 

 slight distance along the thread, bending over, and forming a bend in 

 the thread, and by repeating the process it crowds the thread into a 

 neat coil within its body, where it can be digested. The process is 

 done so systematically and with such evident adoption of the means 

 at hand to the desired end, that it seems as if it must be an adaptation 

 of the ameba to circumstances, the result of long experience or of 

 heredity. That an artificial ameba can perform the same maneuvers 

 seems hardly credible, but it is readily done with almost no difference 

 in detail. If the chloroform drop is given a long fine thread of shel- 

 lac, it proceeds to bend the thread in the middle, and to send pseudo- 

 podia out along the thread to pull it into the drop, coiling it up inside 

 as the chloroform softens the substance of the thread, until it is all 

 contained within the drop, provided, of course, that it is not too long 

 (a thread six times as long as the chloroform drop may be taken in 

 completely). The bending and coiling of the thread in this experi- 

 ment is entirely in accord with the known laws and phenomena of 

 surface tension. 



Fully as striking an ameboid action as the coiling up of a thread 

 too long to be taken in, is the building, by some of the protozoa closely 

 related to the ameba (Difflugia) of a shell which the animal seems 

 to form by cementing together grains of sand, or diatom shells, or 

 other suitable particles. Tlie particles are united so closely and fitted 

 together so well that tliey are almost perfectly free from crevices. 

 Even this process is accurately imitated in Rhumbler's experiments. 

 If a drop of oil is mixed with fine grains of quartz sand, and droi)ped 

 into 70 per cent, alcohol, the grains are thrown out to the surface, 

 where they adhere to the surface of the drop and to one anotlier 

 exactly as do the particles in a difflugia shell. So well fitted are tlie 

 particles that the artificial shell may remain intact for months, and 

 resemble the natural slicll indistinguishably. 



Furthermore, the phenomenon of cell (li\ision can be imitated to 



