June 18, 1897.] 



SCIENCE. 



945 



plain heredity. Darwin's theory of pan- 

 genesis has been pushed aside as a cum- 

 brous impossibility, or at least improbabil- 

 ity. Even the modified theories of De 

 Vries and others are only tolerated. Weis- 

 mann's view, that the chromatic substance 

 is the bearer of heredity, has nearly every- 

 thing to be said in favor of it, if it be ac- 

 cepted that this substance is found in every 

 living cell. But even then, according to 

 the Neo-Darwinian, it has only a very re- 

 mote connection with the somatic micellse. 

 Before resuggesting what has seemed to me 

 a good position that explains details of 

 structure, I may be allowed perhaps to be- 

 come one more of the number of those who 

 have attempted to rehabilitate Darwin's 

 pangenesis hypothesis. 



The wandering of his gemmules to and 

 from definite positions has seemed cum- 

 brous and unlikely, but the most funda- 

 mental law of plant and animal physiology 

 is circulation, metabolism and ultimate as- 

 similation as the physiological groundwork 

 of life, growth and heredity. On the plant 

 side physiologists have only realized within 

 the past quarter- century how potent and 

 generally present are ferments of diverse 

 composition and action. Thanks to the 

 labors of Green, Chittenden and others, we 

 further know that highly complex nitroge- 

 nous compounds are readily converted 

 from solid into liquid form, and can mi- 

 grate, in an as yet often mysterious man- 

 ner, to definite centers of nutrition to be 

 again converted into solids. So far as my 

 knowledge of physics and chemistry leads 

 me, there is no obstacle to our admitting 

 that transfers of complex dissolved ma- 

 terials are passing to the protoplasm, and 

 through it to the chromatin of every cell, 

 more or less affecting its micellar structure. 

 It is necessary, therefore, to learn what rela- 

 tion, if any, exists between the chromatic 

 and plasmatic substance of cells. 



In such plants as Sjnrogyra and Dionoia 



I regard the chromatic substance as being 

 demonstrably continuous from the nucleolus 

 through the nucleoplasm to the cytoplasm, 

 where connections ai-e made with the chro- 

 matic center of each chloroplast. The so- 

 called pyrenoid- centers in Spirogyra be- 

 have to stains and reagents as does typical 

 chromatin substance, while radiating chro- 

 matic threads pass from them to the nuclear 

 chromatin. Furthermore, in Spirogyra an 

 extremely fine chromatic thread- work joins 

 the pyrenoid centers in it transversely or 

 obliquely. What the finer invisible termi- 

 nations of it in the protoplasm may be, we 

 cannot say, but it appears to me that, if 

 physico-chemical laws are not to be thrown 

 aside, it is a necessity of the case that the 

 delicate chromatic endings in the proto- 

 plasm are being acted on, and more or less 

 modified according to the nature of the 

 stimuli that travel to them. As a result of 

 this, a slow, steady but appreciable modifica- 

 tion will be effected in the reproductive cells 

 which epitomize the molecular structure of 

 the entire organism that produces them. 

 John M. Macfablanb. 

 TJnivbesity op Pennsylvania. 



CURRENT NOTES ON PHYSIOGBAPSY. 

 UPLANDS AND VALLEYS OF KANSAS. 



The second volume of the University 

 Geological Survey of Kansas concerns the 

 western part of the State, occupied by Cre- 

 taceous and Tertiary formations. The 

 physiographic matter is contributed by 

 Haworth ; the geological descriptions by 

 Prosser and Logan. The Tertiary lies un- 

 conformably on the broadly eroded Creta- 

 ceous. The surface of the latter, north of 

 the Arkansas and west of the paleozoic 

 area, presents three ragged east- facing es- 

 carpments of moderate height at the mar- 

 gins of the Dakota sandstone, Benton 

 limestone and Fort Hays limestone, with 

 intervening plains gradually ascending west- 



