GENERAL PHYSIOLOGY 189 



1923) and Beers (1924), the sphincter-like ingesting area is powerful 

 enough to cut in two organisms like Paramecium and Frontonia. 

 Ingestion by "importation" finally occurs where a food body, with- 

 out apparent movement on the part of the Ameba, merely sinks 

 into the protoplasm of the captor as in Amoeba dofieini according to 

 Neresheimer. 



In most of these types, which grade more or less into one another, 

 the process of food ingestion may be interpreted as due to local 

 liquefaction in the more solid ectoplasm, and to special conditions 

 of capillarity in the more fluid endoplasm. Rhumbler has shown 

 that a filament of Oscillaria which enters Amoeba verrucosa by 

 " importation " and is too long to be entirely engulfed, becomes coiled 

 up as a result of the physical properties of the protoplasmic mass. 

 In a similar way a filament of shellac may be drawn from water 

 into a chloroform drop in which, by variations in surface tension, 

 it becomes rolled up in a strikingly similar manner. 



Some of these methods of food-getting in holozoic types are sug- 

 gestive of "conscious" activities to a given end. Thus ingestion 

 by " circumfliience " suggests preliminary activities in anticipation of 

 a "square meal." Or traps formed by pseudopodia or by tentacles, 

 or the balloon sails of Pleuronema chrysalis, etc., might be regarded 

 as "set" by Protozoa for the purpose of catching food. Such inter- 

 pretations, however, are more probably evidences of a tempera- 

 mental imagination on the part of the observer than of purposeful 

 activities on the part of these minute organisms. "Sensing" at a 

 distance has been described for Ameba (Schaeffer, 1912), and for 

 Spathidium spathula (Woodruff and Spencer, 1922), and until these 

 phenomena are explained they will continue to serve as a basis for 

 such speculations. Losina-Losinsky (1931) gives good reasons for 

 interpreting all such phenomena as chemiotactic and dependent 

 upon the organizations of captor and prey. 



The so-called "selective" activities of some Protozoa in their 

 apparent choice of food or of building materials for their shells are 

 likewise better interpreted as the outcome of physical conditions 

 of the protoplasm than as purposeful actions of the organisms. 

 Schaeffer (1917) attributes the power of discrimination in food- 

 taking to Ameba, as does Metalnikoff (1908) to Paramecium, a 

 conclusion vigorously opposed by Wladimirsky (1916), who inter- 

 prets negative reactions as a result of depression (fatigue?) in their 

 physiological condition. Actinobolina radians apparently chooses, 

 from a great number of miscellaneous forms, one particular species 

 to harpoon, paralyze and swallow. "This remarkable organism 

 possesses a coating of cilia and protractile tentacles which may be 

 elongated to a length equal to three times the diameter of the 

 body, or withdrawn completely into the body. The ends of the 

 tentacles are loaded with trichocysts. When at rest the mouth is 



