282 THE PROTOZOA 



The emulsification of fats has never been observed, and opinions 

 differ as to its possibility. Meissner ('88) and Greenwood ( '87) asserted 

 upon empirical grounds that it does not take place in Rhizopoda, 

 Heliozoa, or Infusoria. Their evidence is mainly based upon the 

 observations that the fat particles which had been taken in were 

 thrown out unaltered after a number of days. Fabre-Dumergue ('88} 

 and Biitschli ('83) take a less positive view, saying that the possibility 

 of emulsification is certainly not excluded, and that probably a certain 

 amount of the ingested fat is digested. 



Chitin, cellulose, and the shells, tests, etc., of other Protozoa pass 

 through the body plasm with little or no change. Chlorophyl also 

 may be placed in the same category (Meissner, Le Dantec, '92), 

 although a few well-authenticated observations show that in some 



® § & ^> ® (2 



& o & 



Fig. 145. — Starch grains in Ciliata, after partial digestion. [MEISSNER.] 



cases, at least, chlorophyl becomes red, yellow, brown, and finally 

 black (Perty, '52), thus indicating some change in its constitution. 

 There is, however, no evidence to show that it becomes dissolved, 1 

 while the careful observations of Le Dantec ('92) show that in some 

 cases, far from being injured by contact with the plasm, the plant-cells 

 containing chlorophyl may actually thrive in it. Single cells of the 

 alga which Beyerinck ('90) identified as Chlorella vulgaris, belonging 

 to the order Protococcacese, when taken into the protoplasm of Para- 

 mcecium bursaria, are surrounded by a vacuole like any food particle. 

 Soon, however, the vacuole disappears and the plant-cell is left in direct 

 contact with the plasm, where it divides to form a layer of symbiotic 

 algse characteristic of this species of Paramcecium. Thus, in this case 



a substance giving a deep blue color with iodine. This is next changed to (2) Erythro- 

 dextrin (C'i2H2oOio)i8 + H2O, or (Ci2HooOio)i7- (C12H22O11), which is readily soluble in 

 water, and gives with iodine a reddish brown color. Erythrodextrin is converted into (3) 

 Achroodextrin (Ci2H2oOio)o + H2O, or (C, 2 H2oOio)5. (C12H22O11), which is likewise very 

 soluble, tastes slightly sweet, but gives no coloration with iodine. Achroodextrin now 

 breaks up into (4") Isomaltose, which through change in configuration is transformed to its 

 isomere (5) maltose." From Howell ('97), p. 1007. 

 iCf. Biitschli, p. 1802. 



