30 



While the uiflation of the sac is progressing, the size of the 

 mucilage masses in the hair Is perceptibly diminished ; in many 

 of the ruptured sacs, however^ the mucilage is still present in 

 considerable quantities, enclosed as before by actively circulating 

 protoplasm. But it continues to diminish, the vacuoles become 

 larger and larger, compressing, as it were, the mucilage between 

 their convex poles : the edges of the corresponding concavities 

 of the mucilage mass become irregular and jagged (Fig. 15), and 

 finally, in older hairs, the mucilage has disappeared altogether. 

 The plasma has now ceased to live, and appears in Irregular, 

 granular masses and particles scattered through the cell (Fig. 



13). 



Whether, after the bursting of the sac, a second layer of cuti- 

 cle is formed and raised or not, I could not decide to my entire 

 satisfaction. The question would not have suggested itself to 

 me, had I not, in one single case, quite distinctly seen that, a very 

 short time after I had observed the bursting of a sac, the col- 



ft 



lapsed film of cuticle expanded again, and that in a few minutes 

 a complete second sac was formed within the first one, the shreds 

 of which surrounded the upper part of the new bladder (Fig. 16). 

 The latter persisted for six days longer, when it also burst (Fig. 

 r/). The motion of the protoplasm had continued for three days 

 after the formation of the second sac. A small remnant of 

 mucilage stayed at the upper end of the hair, gradually assuming 

 a dark brown color, and had not been secreted a week later, 

 when the observation of the hair was given up. 



With the exception of this one instance, I could not discover, 

 among the large number of hairs examined, a single one that 

 showed the least vestige of a ruptured sac outside of a new one. 

 Besides, a hair which has once produced a sac seems to be 

 deprived of a cuticular layer, for concentrated sulphuric acid or 

 chromic acid will destroy the wall of the hair entirely, leaving 

 only the cuticle of the pedicel cells, and the sac of the hair. 



In order to learn something about the homogeneous, w^hitish 

 substance In the hairs, designated as "mucilage" thus far, several 

 reagents were applied. Glycerin, sugar and alcohol cause the 

 plasma sac to contract in the usual manner. That portion of the 



parietal plasma layer which adjoins the mucilage, barely leaves 



