1910] ‘ CURRENT LITERATURE 315 
with the xylem vessels, and by the “cortical roots” that traverse the “soft bark.” 
An interesting description is given of the behavior of these digesting roots (‘sink- 
ers”’) in penetrating tissue, and in sending out lateral outgrowths (“cortical roots’’) 
which spread extensively through the cortex of the host and in turn give rise to 
other ‘“‘sinkers” that connect with. the xylem. The first infection of a tree is 
brought about by birds, and the subsequent spread of the parasite is caused by 
the falling or washing of berries upon other parts of the host. The seed and 
seedling exhibit unusual resistance to desiccation, and so survive the more or less 
prolonged period of establishment, a period which may extend beyond the first 
growing season. A tree may become affected at any point where living tissue is 
exposed or covered only by a thin layer of cork with lenticels, but the most vul- 
nerable points are the young branches, and sometimes the buds. Various sug- 
gestions are made as to the treatment of trees subject to the attacks of this parasite. 
rhoM. C. 
Latex.—Miss Diana Bruscui has made a study of the latex of five species 
of Euphorbia and three of Ficus,?° in an endeavor to clear up in a measure the 
contradictory results of various investigators, of which the two most recent studies 
by Mouiscu (1901) and KnriEep (1905) are characteristic. Dr. Bruscut finds 
that the quantity of latex, its pressure, and its aspect vary with the season in the 
figs, Ficus Carica and F. pseudocarica, but not the euphorbias. Of = com- 
ponents of the latex the proteins vary in quantity with the season in the two figs 
named, in which they are abundant; but they are scant in F. elastica and the 
euphorbias. The fats are without doubt the most important plastic components 
and they clearly follow the variations in photosynthesis. The starch remains 
an enigma. Re educing sugars increase a little in F. Carica and F. pseudocarica 
but change little in the others. on the whole Miss Bruscut upholds MoriscH’s 
view of the latex as a cell in a living plasma sac, which is not entirely 
aplastic. Inasmuch as it ‘Conta many substances easily utilizable as foods, 
the utilization of these foods is correlated with the activation and activity of the 
related enzymes. ‘The ready use of the fats is certain, and they are the principal 
if not the only plastic material; the indifference of the starch is supposed to be 
due to the lack of an amylase energetic enough to attack it. As the latex tubes 
Tun usually in the midst of organs well supplied with foods by ores Sagem 
their content is yielded only when all other foods are exhausted.— 
Rhizoids of liverworts —WEINERT has investigated the growth and tropisms 
of the rhizoids of Marchantia and Lunularia.?* He finds that light promotes the 
formation of rhizoids from gemmae, and is quite indispensable for the develop- 
ment of the divergent rhizoids of the thallus; further, only a few of the appressed 
2° BRUSCHI, D1ana, Contributo allo studio fisiologico del latice. Annali di Bota- 
nica 7: 671-7oI. 1909. 
*t WEINERT, HAns, Untersuchungen iiber Wachstum und tropistische Bewegungs- 
Serena der Rhizoiden thalléser Lebermoose. Bot. Zeit. 6'71:201-230. figs. II. 
Tg09. 
