300 Phillips on a Comparative Study of the 



through the protoplasmic threads in such of the higher 

 organisms as exhibited them. The almost, if not quite 

 universal, exhibition of intercellular protoplasmic continuity 

 is most significant in this respect. 



In treating the cells of the Cyanophycese with iodine and 

 sulphuric acid, the partition walls are so swollen that the 

 stained protoplasmic threads and the pores are much more 

 evident. In this way every organism studied, was found 

 to have intercellular protoplasmic continuity. When prep- 

 arations are made from material killed in picric acid, their 

 contents stain best to show this feature. In Oscillaria it is 

 quite difficult to demonstrate such, but after the above treat- 

 ment with iodine and sulphuric acid, where trichomes are 

 broken across as seen in Fig. 25, the short protoplasmic 

 connection stands out quite plainly. Some material which 

 was collected and placed immediately in 95 per cent, alcohol, 

 when examined was found to have plasmolized by the rapid 

 withdrawal of water from the cells, so that the material was 

 apparently worthless. But upon re-examining this material, 

 it was discovered that every protoplast still held fast to the 

 cell walls at certain points. Upon careful staining and 

 examination, these points proved to be the places where each 

 protoplast passed through the cell walls to connect with 

 another protoplast, or to form a cilium upon the outer wall. 

 This condition is shown in Fig. 26. At every point where 

 one protoplast is seen apparently attached to a division wall, 

 it will be observed that there is a corresponding attachment 

 of the protoplast of the next cell. While examining some 

 trichomes of Oscillaria that had been stained with iron- 

 ammonia-alum hsematoxylin, and that had slight pressure 

 applied to the cover-slip, the end cell which bore the long 

 finger-like hairs was seen to be pressed somewhat away 

 from the other cells of the trichome (Figs. 43 and 44), and 

 several fine protoplasmic threads were seen connecting it 

 with the other cells. The central thread was always much 

 heavier than the rest, which, though delicate, were still 



