66 A. A. SCHAEFFER 



caused the negative behavior when the first grain of globuUn 

 was presented (372). The negative behavior was certainly not 

 due to lack of hunger, as the succeeding experiments show; and 

 negative behavior was also absent at the beginning of this series 

 of experiments, when gluten was eaten. The most reasonable 

 explanation therefore is that repeated contact with a substance 

 (gluten) possessing comparatively mild food quahties developed 

 a negative condition which had first to be overcome by stimu- 

 lation by the stronger food qualities of the globulin. 



A raptorial ameba which had been treated with several other 

 substances was tested with a grain of gluten (1765). The ameba 

 moved toward the gluten and then passed it on the right without 

 coming into contact with it. Two opposite side pseudopods in- 

 dicating positive and negative tendencies of reaction (see p. 58) 

 were then formed of which the left one moved into contact with 

 the gluten and rolled it along for some distance (1769, 1770). 

 The large pseudopod which was formed on the convex and right 

 side of the left member of the two opposite pseudopods (1767, 

 1768) indicates nearly a balance between positive and negative 

 tendencies of reaction. Had the gluten grain not rolled away as 

 the left pseudopod moved against it, the ameba would probably 

 have moved off through the large pseudopod formed on the right 

 side of the left pseudopod. A pseudopod was thrown out on the 

 right through which the ameba started to move away (1772) 

 without having shown any inclination so far to eat the gluten; 

 but on agitating the gluten shghtly with a glass needle, a food 

 cup was partly formed over it (1773). Ingestion however did not 

 follow. The ameba retracted the food cup and moved on. 



Another raptorial ameba with a long experimental record in 

 which a considerable number of tests were made with various 

 substances and w^hich had partly ingested a grain of aleuronat 

 and a grain of carbon (unagitated) and wholly ingested a grain 

 of globulin, was then presented with a grain of gluten (1872). 

 The ameba flowed directly into contact with it, formed a typical 

 food cup and ingested it (1878). Two pseudopods were sent out 

 presently from the outer rim of the food cup with the gluten in 

 the crotch that was thus formed (1879). The gluten was partly 



