1908] CURRENT LITERATURE © Eg 
water passed through a Pasteur-Chamberland filter, they will remain colorless; 
if kept in such filtered water to which a loopful of a pure culture of the alga has 
been added, they will turn green as completely as if they were kept in unfiltered 
sea-water. Apparently the young animals cannot be infected by cells removed 
from the bodies of older green Convolutas. : 
The green cells are reported to undergo degeneration in the tissues of the 
animal, especially as regards their nuclei, and to this is attributed the inability 
of the green cells to maintain an independent existence, or to thrive in cultures, or 
to infect young Convolutas, when removed from the bodies of older green ones. 
ether under suitable conditions of culture, the algal cells may be able to 
complete themselves, to restore or to regenerate the deficient nucleus, to become 
rejuvenated, is not determined by these experiments. 
The functions of the alga in the body of its host have been experimentally 
studied. The authors conclude that the alga, photosynthesizing sugar, is os- 
motically relieved of a considerable portion of this food. It must diffuse, if it 
remain unchanged, to adjacent cells containing less; but if the sugar be converted 
into starch,the animal cannot digest and absorb it so long as the algal cells them- 
selves live. Soon after infection with the alga, the animal ceases to excrete its 
nitrogenous wastes, and these, absorbed by the alga, are converted by it into higher 
organic compounds, into nitrogenous foods. As many of these as are soluble 
also diffuse into adjacent animal cells. At this stage it would appear that 
both animal and plant profit by their association, the animal gaining a supply 
of sugar and of soluble nitrogenous food, the plant obtaining a steady 
supply of partly elaborated organic nitrogenous food-material. Later on, 
however, the animal ceases to ingest solid food, and there being no other source 
of nitrogenous food than the algal cells themselves, the animal proceeds to devour 
em in its own tissue. Thus it destroys its source of food and ultimately itself, 
but before this it breeds. 
is association, therefore, is similar to that of fungus and alga in lichens, 
where the fungus component, incapable of photosynthesis, is forced to obtain 
hon-nitrogenous food, saprophytically or parasitically. The excreta of the de- 
Pendent component may manure the green plants, but if they do, the benefit 
'S a dubious one, since it leads to destruction without issue. 
A word may well be added to commend the ingenuity of the experiments, the 
care and thoroughness with which they seem to have been carried out, and the 
Pages with which inferences have been drawn from them and stated.—G. J. 
CE. 
: Plant diseases.—A root disease of sugar cane, first described from Java in 1895 
a WAKKER is the subject of a bulletin by Futton.*4 It is characterized by canes 
reduced size and weight, and by reduced leaf system. A large percentage of 
** Futton, H. R., The root disease of sugar cane. Bull. 100, La. Agric. Exp. 
Sta. Jan. 1908, 
