ON SOME PROTEIN CRYSTALLOIDS 87 



They hâve a higher refractive index than the cytoplasm. 



Iodine colours them darkly. 



By Zimmermann's method of staining they were well shown, but not 

 unless the sections were of a thickness of at least 7 p ; which is a disadvan- 

 tage for minute cytological work. 



The hairs in which the crystalloid bodies occur are extremely numerous 

 immediately above the uppermost ovules, and are more sparsely distributed 

 on the lower portion of the placenta. 



I hâve studied them from the time when they are first differentiated 

 from the surrounding epidermal cells, till the withering of the flower, when 

 they degenerate. In young ovaries (about three millemetres in length, in- 

 cluding the pistil), the upper ovules of which show four nuclei in the 

 embryo-sac, the hairs are only slightly larger than the other epidermal cells, 

 fig. l,a, and are not specially rich in cell protoplasm, although the nucleus 

 stains deeply. 



In ovaries five millemetres long, at the time when the embryo-sac first 

 contains eight nuclei, the hairs hâve elongated greatly, and are remarkably 

 rich in protoplasm, and in nuclear chromatin, and, with few exceptions, 

 each hair possesses several (2-6) nucleoli, figs 2 and 3. At this period any 

 appearance of erythrophilous bodies outside the nucleus is extremely rare. 

 A few hair-cells may hâve undergone division ; but, as a rule, they continue 

 to be unicellular throughout life. Dumb-bell shaped nuclei, fig. 3, are very 

 common, both at this period and later. I examined 50 cells of this stage, 

 making careful drawings of each sériai section, and found that there were as 

 follows : 



Hairs with three to six nucleoli 14. 



Hairs with two nucleoli 24. 



Hairs with one nucleolus 12. 



Only two cells of the total number contained crystalloids or granules; 

 and thèse occurred in the lower, better nourished, and therefore more ma- 

 ture part of the ovary. One of them had one nucleolus; and the other 

 contained two. 



On the examination of the ovary of a bud about seven millemetres long, 

 numbers of erythrophilous granules and slender crystalline rods are found 

 in the cytoplasm. I believe the granules are also crystalline in form ; but, 

 they are usually so very small, that I hâve not satisfied myself on this point, 

 figs. 4 and 5, cr and crk. 



