to the Plant Cell. 
5 2 5 
into various saccharides. Loew and Bokorny (’87) reported that glucose 
occurs in demonstrable amounts in cells of Spirogyra during the process of 
conjugation, and also in cells which slowly perish in unfavourable con- 
ditions. It may be possible that these cells normally form glucose, and 
that its accumulation is due to the fact that the machinery of the cell is in 
no condition to make proper use of it. 
The results of various experiments agree in showing the necessity of 
phosphorus for the production of proteids and proteid-like bodies. The 
injurious effect upon enzyme formation is, perhaps, analogous to the rapid 
disappearance of the water-soluble forms of phosphorus from the cell in 
cases of phosphorus-starvation observed by Koch and myself (’07). The 
diastase would probably be one of the first components of the cell to dis- 
appear. since, as I have shown in a former paper (’04), the production of 
enzymes is quickly influenced by external conditions. 
The separation of the cells of the filaments from each other was 
probably brought about through conditions which dissolved the middle 
lamella of the cell-wall. The middle lamella, as first pointed out by 
Payen (’46), is mainly composed of calcium pectate, but in young 
unmodified cell-walls a considerable quantity of pectose is present, and 
a correspondingly smaller amount of calcium pectate. In the cell-walls 
under consideration, pectose undoubtedly forms a part of the middle 
lamella. Apparently the conditions brought about in the cell through 
the absence of phosphorus resulted in the formation of some substance 
in the cells (or in the culture-solutions), which dissolved the calcium 
pectate and pectose, and allowed the cells to separate. This question 
seems worthy of more extended study than I have been able to give it. 
To study the role of phosphorus in germination I made several cultures 
of moss spores. Part of the cultures were made in the complete nutrient 
solution, and others in solutions containing all necessary elements except 
phosphorus. The spores were obtained from a species of Atrichum , and 
cultivated in solutions from March 9 to May 10. On the latter date the 
complete nutrient solutions contained large branched protonemata, which 
were developing buds and rhizoids. In the solutions lacking phosphorus 
there had been no germination of the spores. 
With different solutions and different species of mosses, Schoene (’06) 
was able to germinate spores on phosphorus-free nutrient solutions. 
Fnnaria hygrometrica spores germinated, but produced only rhizoids in 
place of the normal protonema. Bryum caespiticimn spores germinated 
on the deficient solutions, forming protonemata of an inferior size relative 
to the controls. The small protonemata grew for about ten days, and then 
began to turn brown at the apices. The injury would spread within a few 
days until the entire protonema was brown and all activity ceased. 
The process of mitotic cell-division was studied in the absence of 
