Geology and Natural History. 343 



termed by him linin ; that of the basic substance, paralinin ; that 

 of the nucleoli, pyrenin ; that of the peripheral envelope, amphi- 

 pyrenin : while in the fibrillar framework is distributed chroma- 

 tin. The chlorophyll granule is believed by him to possess nu- 

 merous fibrillse imbedded in a basic substance and surrounded 

 by a plasma-membrane, but the fibrillar character is detected 

 only when the granules are swollen by immersion in water, and 

 a portion of the basic substance is dissolved. Schwarz distin- 

 guishes two proteids in the above, chloroplastin and metaxin. 

 The author's earlier studies under Pfeffer naturally led him to ex- 

 periment upon the subject of precipitation-membranes and the 

 allied one of vacuolation. He holds that when there is a mix- 

 ture of two substances, one of which is soluble and the other 

 insoluble but capable of limited enlargement by imbibition, there 

 can be vacuolation ; but in a mass of homogeneous substance 

 there can be no vacuolation. The author has conducted many in- 

 teresting experiments relative to the behavior of the different 

 pi'oteids with regard to digestive ferments, and also with regard 

 to the action of various metallic compounds. 



E. Belzung (Ann. Sc. nat. bot. iv, 179, 1887) has criticised 

 Schimper's views relative to the formation of starch-grains through 

 the agency of the starch-accumulators (leucoplasts). He states 

 that in many instances the bodies described by Schimper could 

 not be found, and that in many of the cases where they were seen 

 they did not bear out Schimper's theory. In a rejoinder (ibid. 

 VI, v, p. 77) Schimper demonstrates defects in Belzung's observa- 

 tions and shows that he has no reason to modify his original con- 

 clusions. 



Heinricher (Mitth. bot. Inst, zu Graz, 1) has pointed out the 

 occurrence in the tissues of certain Cruciferse of idioblasts which 

 he terms albuminoid-sacs. »They are best seen in sections par- 

 allel to the plane of the leaf, in alcoholic material treated with 

 Millon's reagent or in material which has been acted on by boil- 

 ing water. The sacs or vesicles are more or less curved and are 

 generally simple. 



It has been known from researches by Hansteiu and DeVries 

 that when certain fresh-water Algse are placed in^a nutrient plas- 

 molytic solution, for instance, a ten per cent solution of glucose 

 or a twenty per cent solution of cane-sugar, the shrunken proto- 

 plasmic mass still remains living and even manifests some phe- 

 nomena of growth. At this point Klebs (Ber. deutschen bot. 

 Gesellsch., 1887, p. 189) takes up the subject, showing that it is 

 possible to examine in this manner the mode of growth of the 

 cell-wall. He concludes from his observations that in the case of 

 Vaucheria the growth is by apposition in the newer walls and by 

 stretching in the enlargement of the older walls. He examined 

 also the relations of growth under these conditions to the sur- 

 roundings, but of these results he has given only a general out- 

 line. The following statement relative to the nucleus is of con- 

 siderable interest. From experiments on the cells of Zygnema and 



