11. A PLOEA WITHIN ANIMALS. 23 



The granules are more or less minute, transparent, colorless, or occasionally 

 faintly yellowish, spherical bodies, measuring from a mere point to the xo'o'To' ^^ 

 an inch in diameter (Fig. 10). They exist in variable quantity within the prin- 

 cipal cell, usually more or less enveloping the globules, but never to such an extent 

 as to exclude the latter, although they are themselves sometimes reduced to a few 

 scattering points among a mass of globules. Usually, they are most abundant at 

 the bottom or commencement of the cell (Figs. 6, 9), and rapidly diminish towards 

 the distal extremity of the latter. Sometimes they are abundant at the bottom 

 (Fig. 6), and do not exist at all near the distal end of the cell (Fig. 4); at other 

 times they are found at both ends but none in the middle (Figs. 1-3) ; and lastly, 

 they are occasionally met with towards the distal extremity of the cell only. 



These granules somewhat resemble oleaginous particles in appearance; they are 

 highly refracting, and are more dense than the surrounding protoplasma. 



The globules, as I technically designate them, are colorless, transiDarent, spheri- 

 cal, polyhedral, or oblong bodies. When spherical, they are always accompanied 

 by a more or less large quantity of protoplasma and granules (12). When poly- 

 hedral they ex;ist in large number, and the form appears as an alteration from the 

 spherical produced by mutual pressure (2, 14). When oblong, their long diameter 

 is generally parallel to the length of the cell containing them, and ascends to three 

 or four times that of the transverse diameter, which in such cases is always that of 

 the caliber of the cell (PL II. 4 ; III. 8). Sometimes they are met with transversely 

 oblong (2), the long diameter equal to the caliber of the cell, the short diameter 

 always less than the latter, the form being apparently produced by upward pressure. 



In size, the globules usually measure from one-sixth to the whole diameter of the 

 caliber of the containing cell. 



Sometimes they exist almost to the entire exclusion of the ordinary granular 

 matter, or even the intervening protoplasma (PI. II. 1; III. 2, 13, 14). Sometimes 

 they are of remarkably uniform size in the same cell, though very variable in this 

 respect in different cells (17) ; frequently, however, they vary very much in size 

 within the same cell (PI. II. 4). Occasionally, a single row of large globules distends 

 the cell nearly throughout its whole length (PL III. 13) ; at other times, three or 

 more rows are observed, polyhedral in form, regularly alternating with one another 

 (17) through the whole course of the tube, if the latter remains uniform in diame- 

 ter, or cylindrical; should the tube become clavate, or more dilated at the distal 

 end, it is always attended by an increase in the relative number of globules (4). 



In physical structure, the globules appear to be composed of a somewhat viscid, 

 amorphous, hyaline, albuminoid liquid, inclosed within an immeasurably thin, amor- 

 phous membrane, apparently a delicate film of coagulated protoplasma, holding a 

 mass of the same substance in a liquid condition. 



Upon the application of a weak solution of iodine in water to the living thallus 

 of Enterobryus, a movement is observed to take place in the contents of the princi- 

 pal cell in an upward direction, or towards the distal end, apparently as if the cell- 

 wall were contracting, and there was less resistance anteriorly than posteriorly, and 

 the cell-contents were consequently pushed in the former direction. A moment 



