556 ASA A. SCHAEFFEE 



mine produces about the same reactions as the mixture of car- 

 mine and egg white. Pure carmine is ingested readily, although 

 after a few minutes' sojourn in the ameba's body, it is excreted. 



Pure carmine is usually regarded as a waste substance as far 

 as its nutritive value is concerned. But there are no studies on 

 record that show this as far as I have been able to find. Chemical 

 analyses have been made (Liebermann, Jour. Soc. Dyers, 1885, 

 I, 269) from which it appears that some free tyrosin is probably 

 present in some grades of carmine, but Millon's and Piria's tests 

 for tyrosin did not show its presence in the carmine I used. 

 When carmine is thoroughly shaken up with tap water, examina- 

 tion of the filtrate showed the presence of a considerable quan- 

 tity of some organic acid and some salt of aluminium. 



One of the properties of carmine which doubtless affects the 

 reactions of ameba is solubility. If some carmine is placed in 

 clean tap water enough of it will go into solution in a few days to 

 color the water a very decided crirnson. Such a solution of car- 

 mine does not seem to have a deleterious effect on ciliates or rhiz- 

 opods, if these are immersed in the solution for days and weeks, 

 as numerous observers have testified. Nor does the continual 

 eating of carmine for days and weeks appreciably injure Para- 

 mecium or stentor (Metalnikow, '07, Schaeffer, '10). The short 

 stay of carmine in the ameba's body cannot be due, therefore, to 

 the injurious action of the carmine. 



As stated above, carmine is eaten readily whether in the pure 

 form or mixed with a slight amount of egg white. But it is eaten 

 readily only by the granular amebas; the raptorial forms eat 

 carmine relatively very seldom, and then not with readiness. 



Let us now take up the reactions of a granular ameba toward 

 carmine as portrayed in figures 1 to 152. A grain of carmine of 

 grade 2 was placed to the right of the ameba's path — 1. Al- 

 though the ameba moved forward in a straight path, the tip of 

 the ameba turned directly toward the carmine grain. The proto- 

 plasmic stream then forked, one stream resuming movement 

 straight ahead, while the other moved toward the carmine until 

 it came into contact with it. All the protoplasm then began 

 streaming toward the test object. A food cup was formed by 



