676 INTERNAL SECRETIONS AND PRESERVATION OP LIFE. 



trate directly into the vacuole between the external layer of 

 granules is not alone to suggest that such is the case, but the 

 manner in which the leucocyte takes up stains likewise does 

 so. As can readily "be seen, the absorption of the dye by the 

 cell occurs without involving any alteration of its shape which 

 can at all be associated with the process. That the absorption 

 cannot occur through the visible canaliculi, i.e., those that take 

 stain because they constantly contain fluid, is rendered very 

 probable by the presence of the granules, which must entirely 

 close their external orifices. It must occur, therefore, through 

 paths presenting some analogy to the pores of certain sponges, 

 which allow the surrounding water to pass into the interior of 

 the sponge, so long as it does not carry any harmful products 

 along with it (Metchnikoff). And yet the fact that such a sys- 

 tem of channels does not exist is shown by the promiscuous 

 directions taken by bacteria in penetrating into the cell. In- 

 deed, their bodies are not directed axially toward the peri- 

 nuclear vacuole; they seem, once within the external layer of 

 granules, to point in almost any direction. We are brought 

 back, therefore, to the soft, yielding, protoplasmic cell-sub- 

 stance of the amoeba, which will allow liquids to easily transude 

 through it, and the more dense materials to cleave their path 

 into it and down to the vacuole, without leaving a wound 

 behind them. "On introducing pigeon leucocytes filled with 

 anthrax bacilli (to which the pigeon is very refractory) into 

 bouillon," says Metchnikoff, "bacilli grow, pierce the proto- 

 plasm of the cells, and form well-developed filaments, showing 

 definitely that the bacilli were inglobed in a living condition." 

 We might say "ingest," however, for the perinuclear vacuole 

 asserts its identity as a digestive organ the familiar digestive 

 vacuole in several ways: i.e., as a cavity in which all the 

 materials that supply the cell with functional energy, i.e., 

 with life, are drawn. 



Metchnikoff, 8 referring to the intracellular digestion to 

 which amoebae submit the materials they ingulf, writes as fol- 

 lows: "A closer observation of the group of protozoa compels 

 us to the conviction that this digestive function must play an 



8 Metchnikoff: "Lectures on the Comparative Pathology of Inflammation," 

 translated by P. A. and E. H. Starling, pp. 18 et seq., 1891. 



