1689.] MICROSCOPICAL JOURNAL. 113 



BIOLOGICAL NOTES.* 



Development of Macrospores of Isoetis lacustris L. — Prof. 

 Vines, in a communication to the Royal Society of London, January 

 31, concerning Isoetes macrospores, says that the protoplasm contains 

 large quantities of oil and starch, and is provided with a large nucleus, 

 in which are imbedded certain bodies, which appear yellow in prepa- 

 rations stained with hematoxylin, but as to whose nature it is not at 

 present possible to speak definitely. During germination hematoxylin 

 fails to reveal the presence of a nucleus, and the cytoplasm at this period 

 stains so uniformly and deeply that it is possible that the nuclear substance 

 may be diffused through it. It is when stained thus deeply that the first 

 indications of cell formation appear. The mass of protoplasm seems to 

 be traversed by "cracks," which divide it into a few large and isolated 

 parts, and it is in the direction of these cracks that the wall of the new 

 cells first appears. Prof. Vines infers that the cracking of the proto- 

 plasm is due to changes which have already occurred in the protoplasm 

 preparatory to the formation of cell-walls. After the formation of the 

 cell-walls the nucleus again appears distinctly in each cell. 



The effect of girdling a tree. — The American Journal of Science 

 (vol.. xxxvii, p. 79) cites from the Canadian Record of Science the ac- 

 count of a pine tree that has lived a number of years (probably 15) after 

 having been completely girdled. The circumference of the tree above the 

 girdling is 26.5 inches, while below it is only 19.5. While the cambium 

 layer above the ring is in a perfectly normal condition, below it is dead 

 for some inches. The foliage shows signs of decaying health. 



Assimilation of chlorophyll-bearing cells. — Th. Bokomy of 

 Erlangen is also reported (same citation) as having found that the as- 

 similating cells of spirogyra are capable of assimilating methyl-alde- 

 hyde, methyl-alcohol, and glycerin. Formic aldehyde killed the proto- 

 plasm. This is of interest since, according to Baeyer's hypothesis, car- 

 bon dioxide, under the influence of chlorophyll acted on by sunlight, is 

 converted into carbon monoxide, which takes up a molecue of water, 

 converting it thereby into formic aldehyde, which, in the presence of 

 free alkalies, can be changed at once to sugar. N 



Peripatus. — Mr. Arthur Dendy reports (Nature, v. xxxix, p. 366) 

 a new species of peripatus found in Victoria. Mr. Adam Sedgwick, 

 however, in a subsequent issue (p. 412) doubts the distinctness of this 

 species on account of the great variation in the known species of this 

 exceedingly interesting genus. Mr. S. reports peripatus also from Car- 

 silis, New South Wales. 



Deteriorated air. — M. Th. Schloesing, in a communication to the 

 Paris Academy of Sciences, claims that the injurious effects of breathing 

 exhaled air are not due to the presence of carbon dioxide, but to 

 other substances given off by the lungs during respiration, and espe- 

 cially in the cases of person suffering from pulmonary diseases. Tests 

 made by Brown Sequerd and d'Arsenval proved that air containing 20 

 per cent, of carbon dioxide can be breathed for one or two hours with- 

 out any marked inconvenience or lasting consequences, whereas air ex- 

 haled from tuberculous lungs may prove fatal even in very small doses 



*This department is conducted by Prof. J. H. Pillsbury. 



