



1901] CURRENT LITERATURE 281 
plants,’ describes new species under Arabis, Trifolium, Astragalus, Solidago, 
Erigeron, Antennaria, Artemisia, Crepis, Dodecatheon, Gilia, Phacelia, Lap- 
pula, and Mimulus.—L. M. UNDERWOOD (2ézd. 46-47) has described a new 
Adiantum from New Mexico.—J. M. C 
BROWN and EscomMBE have under way one of the most important physical 
researches of recent years. They have set forth some of their results and 
have applied them to plant functions in a paper on the “Static diffusion of 
gases and liquids in relation to the assimilation of carbon and translocation 
in plants.” "3 Blackman’s interesting results (1895) concerning the diffusion of 
CO, through stomata are fully substantiated. The authors further find that 
with small openings a) the rate of diffusion varies as the diameter of the 
orifice; 4) multiperforate septa do not hinder diffusion when the openings 
are about ten diameters apart; ¢) decrease in per cent. of area of holes is not 
followed by proportional decrease in amount of diffusion; @) the laws hold for 
both gases and solutes. Assuming an analogy with lines of force about an 
electrified disk, they find these results accord with mathematical calculations. 
Applying these principles to plants the authors conclude that 1) in an ordinary 
leaf (Helianthus annuus) the stomata are sufficient to permit the diffusion of 
five or six times as much as CO, as is actually used by the plant; 2) resistance 
to the absorption of a greater quantity of CO, lies in the relatively slow diffu- 
sion of the CO, after solution; 3) the stomata are more than sufficient to 
permit the escape of the observed amounts of water vapor by diffusion with- 
out any mass movements; 4) continuity of protoplasm may have more to do 
with translocation of foods than has been supposed hitherto, since over 60 
per cent. of diffusion possible through an orifice the full size of the pit would 
take place through the many minute perforations, although their area. be 
only 0.84 per cent. of the total membrane of the pit.—T. C. Fry 
IN A RECENT PAPER by A. H. R. Buller™ on chemotaxis in fern sperms it 
is shown that these cells are attracted not only by malic and maleic acids 
and several of their salts (as was known before), but also by numerous salts 
of the inorganic acids. Potassium and sodium tartrate and potassium 
oxalate also attract. Sperms of Gymnogramme Martensit were used an 
were tested by Pfeffer’s method of capillary tubes. The concentration nectes- 

sary for attraction is usually = to + normal. With malic acid it is =, to 
<=» and with sodium malate *. to %. Nitrates and chlorids of sodium, 
ammonium, and calcium do not attract, nor does lithium nitrate. The choice 
of compounds to be tested was made, apparently, with the aim of making a 
catalogue of attracting substances rather than of determining the real nature 

3 Phil. Trans. Roy. Soc., London, B. 193 : 223-292. 1900. 
Contributions to our knowledge of the physiology of the spermatozoa of ferns. 
Ann. Bot. 14: 543. 1900 
