182 



SCIENCE 



[X. S. VOL.XXXII. No. 814 



Alkylamines as Products of the Kjeldahl Di- 

 gestion," by C. C. Erdmann. A method for 

 the qualitative detection and approximate 

 quantitative estimation of alkylamines in the 

 presence of ammonia. Alkylamines were ob- 

 tained from the product of the Kjeldahl diges- 

 tion of methyl urea, creatin, creatinin and 

 lecithin. " On the Alleged Occurrence of Tri- 

 methylamine in TJrine," by C. C. Erdmann. 

 Fresh, normal urine does not contain tri- 

 methylamine. "The Study of Autolysis by 

 Physico-chemical Methods, IL," by Eobert L. 

 Benson and H. Gideon Wells. A discussion, 

 with experimental data, of the value of estima- 

 tions of freezing point and electrical conduct- 

 ivity in the study of autolysis. " A Method 

 for Treating and Preserving Large Quantities 

 of Urine for Inorganic Analysis," by Edgar 

 F. Slagle. Add sulphuric acid and evaporate 

 to dryness. "Phosphorus in Beef Animals, 

 Part IL," by C. K. Francis and P. F. Trow- 

 bridge. Analytical data showing percentages 

 of water, fat and phosphorus in various parts 

 of cattle. "Note on Chemical Tests for 

 Blood," by P. A. Kober, W. G. Lyle and J. T. 

 Marshall. Tannic acid interferes with vari- 

 ous common reactions for blood, hence water, 

 not tea, should be given in test meals when the 

 presence of blood is suspected. . 



A NEW PRINCIPLE IN THE MEGBANISM 

 OF NUCLEAR DIVISION 



The present conception of the causes, which 

 determine the movements of the chromosomes 

 and achromatic constituents of the nuclei of 

 vegetable cells, can hardly be said to be in 

 accordance with our views concerning the 

 mechanical causes of other movements of 

 plants. 



It assumes contractility of protoplasmatic 

 parts and affinity between homologous organs 

 as the chief forces in play, but this assump- 

 tion is evidently not sufficiently supported 

 by what we know about contractility and 

 organic affinity in other domains of physiol- 

 ogy. 



In a recently published paper, prepared in 

 the laboratory of Strassburger, in Bonn, Mr. 

 Theo. J. Stomps proposes a new principle for 



the explanation of the mechanism in question.' 

 It is based on our knowledge of the function 

 of osmotic forces in the growth of cells and 

 in the movements of plant-organs and simply 

 assumes the same forces for the process of nu- 

 clear division. 



About forty years ago Sachs discovered 

 the now universally acknowledged fact that 

 growth and related movements, such as geo- 

 tropism and heliotropism, are determined by 

 the distending of the cell walls through the 

 osmotic activity of the cell sap. The tension 

 of tissues in growing parts was found to be 

 due to the same cause, as were the reactions 

 of sensible stamens to the stings of insects 

 and of the motile organs of leaves to the 

 changes in the intensity of the light. 



At that time the presence of vacuoles with 

 cell sap in very young cells, during their meri- 

 stematic condition, was still unknown. This 

 important fact was since discovered by Went, 

 who proved the individuality and continuity 

 of these vacuoles in the same way as this had 

 been done for chloroplasts by Schmitz and 

 Sehimper. The foamy condition, which is 

 now found to be so general in the protoplasm 

 surrounding nuclei during their division, is 

 due to the presence of numerous small vacu- 

 oles filled with cell sap. The walls of these 

 vacuoles are to be considered as living parts 

 of the protoplasm and as active in the secre- 

 tion and accumulation of those substances 

 which determine the osmotic pressure of the 

 cells. These vacuoles may divide themselves 

 or unite in groups into larger ones in the same 

 way as these changes have so frequently been 

 observed in older cells. 



Starting from observations on the behavior of 

 the chromosomes during the nuclear divisions 

 in Spinacia oleracea and other plants, and es- 

 pecially from their visible changes during the 

 synapsis and the reduction-divisions which 

 prepare the production of the sexual cells, Mr. ' 

 Stomps proposes a new principle for the 

 mechanical explanation of these phenomena 

 in general. 



' Theo. J. Stomps, " Kerndeeling en Synapsis by 

 Spinacia oleracea L.," Amsterdam. 1910. 



