rrr] CURRENT LITERATURE 477 
dia; and also a study of Thielaviopsis paradoxa, recently found to be the 
cause of a stem disease of the cocoanut palm in Ceylon. 
In other Circulars issued during the latter part of 1910, E. E. Green 
presents a “Report on the outbreak of Achatina fulica,” a ravaging snail; 
Ketway BAMBER and R. H. Lock discuss “ The effect of different inter- 
vals between successive tappings in Para rubber (Hevea brasiliensis)”; Reports 
on “Cotton growing in Ceylon” and on ‘Cymbopogon grass oils in Ceylon”’ 
are published; and Director J. C. WILLIs presents the first of a series of direc- 
tions as to “School gardening and nature study.” WILtIs* has published 
also the first instalment of a revision of the apie of the vascular plants of 
Ceylon, published by TRIMEN in 1885.—J. M 
Effect of strontium salts on ees oe chemical properties of calcium 
and strontium agreeing more closely than those of sodium and potassium, 
one might expect to easily substitute strontium for calcium in physiological 
relations. Investigations along the animal side have been to the contrary, 
and Lorw” has endeavored to gain further knowledge by tests with species of 
Spirogyra especially. Chemically equivalent solutions of calcium chloride 
(x per cent) and strontium chloride (1.7 per cent) were used separately. The 
filaments remained for months in the calcium chloride practically intact. 
In the strontium chloride the per Se effects were manifested slowly, but 
within a month the chloroplasts ame yellowish-green, less active in 
starch-making, and finally the cells die d. In the strontium solution needle 
crystals developed in the cells, something which did not occur in the calcium 
solution. It appears obvious to the author that such crystals represent a 
combination of strontium with organic acid. Since the algae endure the 
strontium salt longer than any other except calcium, it seems that strontium 
does not rapidly displace from important positions in the protoplasm oe 
metallic elements such as potassium and magnesium. According to aw 
of mass-action such a displacement would be expected. A discussion 2 why 
strontium does not physiologically replace calcium leaves the reader with 
little to cling to.—Raymonp H. Ponp 
Anatomy of Riccia.—Taxonomists separate the genus Riccia into two 
subgenera, Euriccia and Ricciella. In the former the dorsal region of the thallus 
consists of columns of cells split at the corners, each 4 columns of cells thus 
inclosing a long narrow air chamber having no lateral communications; in the 
latter, flat lamellae bounding the relatively large air chambers. STEPHANI, 
however, studying R. vesiculosus, in which 8 cells bound the air chamber, 
places this form in the subgenus Ricciella, and says: “ Dividing the genus into 
"9? Petcu, T., Thielaviopsis paradoxa (de Seynes) v. Héhnel. Idem 511-574. 
*° Witus, J. C., A revised catalogue of the flowering plants and ferns of Ceylon. 
Idem 467-510. 
** Loew, Oscar, Ueber die se von Strontiumsalzen auf Algen. Flora 102: 
96-112. 1911 
