1907] CURRENT LITERATURE 79 
to the withdrawal of water. GorKE goes a step further and shows’? that the 
low temperatures besides producing various analogous changes, lead to intra- 
molecular transpositions in the proteids, which are generally accompanied by a 
precipitation of a part of the dissolved ones; and when such chemical alternations 
surpass a definite limit death ensues.—C. R. B 
Sap-flow.—WIEGAND gives a useful résumé of the facts and theories in 
regard to the flow of the sap from bleeding trees, especially the maple, to which 
he adds some observations of his own. He holds that the bleeding due-to pres- 
sure of expanding gases is inadequate to account for the volume of sap exuded, 
and that the best explanation is the one that ascribes the pressure to the excretion 
of water by cells of the medullary rays, stimulated to activity by rising 
temperature.—C. R 
_ Glycogen and paraglycogen.—Since Massart’s edition of ERRERA’S post- 
humous paper on this subject,3? drawings have been found and copied with 
“scrupulous fidelity.”” These are now issued as a supplementary paper.’ The 
five plates are handsome chromolithographs showing the distribution of glycogen 
and paraglycogen in the rhizopods and flagellates, as well as several pope of 
fungi, including the Myxomycetes.—RayMonpD H. Ponp 
Cotyledons of Trollius—RAMALEy>4 has found that the petioles of the coty- 
ledons of Trollius albiflorus are united for about half their length, the plumule 
nO id through a slit in this sheath. Lussock described a similar ones 
nT. Ledebouri, and it seems to be general throughout Ranunculaceae.—J. M. C 
Mycorhiza and nitrogen fixation.—Contrary to the supposition of MULLER, 
MG ter finds that the dichotomous mycorhiza of the mountain pine is of no 
use in fixing free nitrogen for the tree.2s—Raymonp H. Ponp. 
Anatomy of roots.—Horm?° has described and illustrated the anatomical 
Structure of the roots of species of Spigelia, Phlox, and Ruellia—J. M. C 
Ee 
3° GorkE, H., Ueber chemische Vorginge beim Erfrieren der Pflanzen. Landw. 
Versuchs-Stat, 6s: 2149-160. 1906 
3* WrEGAND, K. M., Pressure and flow of sap in the maple. Amer. Nat. 40: 
499-453. 1906. 
3? See review in Bot. GAZETTE 411370. 1906. 
Recueil de 
33 ERRERA, LEo, Dessins relatifs au oir et au paraglycogen. 
PInstitut bot. Bruxelles 1: 432-436. pls. 5. 1 
4 Raw FRANCIS, ae seed and nici of the mountain globe-flower. 
Univ. ieee Studies 3193-05. figs. I3. 190 
35 M6LLER, A., Mykorhizen und kaa ndiies Ber. 
Gesells. 24:230-233. 1906. 
Hom, THEOo., The root-structure of Spigelia marilandica L., Phlox ovata Ls 
and Ruellia ¢ ills Pursh. Amer. Jour. Pharmacy 78:553-559- figs. 5- 1906. 
Deutsch. Bot. 
