February 20, 1914] 



SCIENCE 



295 



These results are quite different from those ob- 

 tained by inoculating etiolated plants with sapro- 

 phytic fungi. Under such conditions, in some cases 

 at least, saprophytic fungi are able to develop on 

 the living tissues. 

 Besistance of Certain Fern Prothallia to Extreme 



Desiccation: D. M. Mottier. 



The prothallia of Camptosorns rhizophyllus and 

 of other forms found on dry hillsides and on lime- 

 stone cliffs have been subjected to conditions ap- 

 proximating prolonged drought in the natural en- 

 vironment and to conditions of extreme desiccation 

 in the laboratory. The part the prothallia play in 

 the ecological adaptation of these ferns is shown 

 by their survival of the most extreme laboratory 

 conditions and by their subsequent production of 

 sporophytes. For example, prothallia of Campto- 

 sorns survive exposure to glycerine-dried air for a 

 period of six weeks, and those of other genera even 

 a more extended desiccation under similar and dif- 

 ferent conditions. A continuation of work pub- 

 lished in the November number of the Bull. Torr. 

 Bot. Club. 

 The Pyrenoid of Anthoceros : F. McAllister. 



All of the cells of the gametophyte of Anthoceros 

 Imvis contain a single large chloroplast, each of 

 which has near its center a pyrenoid. The pyrenoid 

 is not a homogeneous, kernel-like structure, as is the 

 case in the algae, but is a multiple structure made 

 up of a dense group of from 25 to 300 disc- or 

 spindle-shaped bodies. These bodies are protein 

 according to the standard microchemical tests. 

 During photosynthesis the outer bodies are trans- 

 formed directly into rudimentary starch grains 

 while new bodies seem to be formed in the interior 

 of the mass by fission. The rudimentary starch 

 grains increase in size as they are pushed toward 

 the periphery of the chloroplast by younger starch 

 grains. 



In the embryonic tissue of the sporophyte the 

 pyrenoid can not be identified, but as these cells are 

 pushed upward scattered bodies seem to aggregate 

 in the center of the chloroplast to form it. When 

 fully formed it differs in no way from the pyrenoid 

 of the gametophyte. In the sporogenous layer, 

 however, no pyrenoids are visible and the abundant 

 starch grains of the spore mother-cells and the 

 spores seem to be formed much the same as in 

 other Bryophytes. 

 Physical Factors in the Cleavage of Ccenocytes : E. 



A. Harper. 



In the Myxomycete TJidymium we have the spores 

 formed by progressive cleavage essentially as in 



Fuligo and the sporanges of the Mucorinese. The 

 presence of a eapillitium of radial fibers, however, 

 apparently makes possible the manifestation of cer- 

 tain factors in the process of division which are not 

 so easily recognizable in other cases. The first 

 visible step in cleavage seems to consist in the ex- 

 trusion of water from the protoplasm. This water 

 collects to form from one to several vacuole-like 

 bubbles on the capillitial threads. Further contrac- 

 tion and extrusion of water goes on till each capil- 

 litial thread comes to be enclosed by a watery 

 sheath. Progressive cleavage by furrows now sets 

 in from the surface of the spore sack and from the 

 surface of these water sheaths around the capil- 

 litial threads. Ultimately we have uninucleate 

 spores. The whole process seems to involve active 

 extrusion of water, and if we conceive that the 

 chemical constitution of the nuclei is such as to 

 favor the retention of moisture in the cytoplasm 

 immediately adjacent to them we should have a 

 condition which would tend toward the orientation 

 of the cleavage furrows in such a position as to lead 

 ultimately to the production of uuinucleated spore 

 masses. 



The Harmful Action of Distilled Water: B. H. 



True. 



It appears probable that the problem of injury 

 by distilled water is not a simple one capable in all 

 cases of a like explanation. In some cases, distilled 

 water obtained from apparatus having copper sur- 

 faces exposed to contact with the water undoubt- 

 edly derives certain toxic properties from minute 

 traces of copper. In other cases, doubtless, it is pos- 

 sible for other harmful impurities to find their way 

 into the product, but after the action of all the 

 impurities has been accounted for there still re- 

 mains a residuum of harmful action due to no 

 known type of impurity. This mode of harmful 

 action seems to be most marked in water which 

 shows the highest resistance to the passage of the 

 electric current. 



Samples of distilled water which show the high- 

 est resistance are in general more harmful to 

 lupine roots than waters containing a large quantity 

 of electrolytes. These same samples of water 

 withdraw electrolytes from the tissues of the 

 roots when they remain in the water. This leach- 

 ing of electrolytes is shown to be the probable 

 mechanism by means of which purer samples of 

 distilled water exert their harmful action on the 

 roots. This action has a physical osmotic com- 

 ponent, but for the roots of Lupinus albus, this 

 osmotic factor seems to be decidedly secondary 



