BOTANICAL GAZETTE. 87 



mea, and have admired it for its graceful habit. The sterile fronds 

 o-ently curve backward so that the fertile fronds always stand erect 

 in the center of the urn-shaped growth. There has been no change 

 for ten years in the manner of development till the present season. 

 Now two of the fertile fronds are partly sterile; in one the tip of 

 the frond, for 13 pairs of pinnae, is fertile, then two pairs partly 

 fertile, the remaining 5 pairs not being distinguishable from the 

 entirely sterile fronds; the other has the tip and base sterile, and 3 

 pairs of pinnae out of the central portion fertile, and one pair part- 

 ly fertile. Although the change from the fertile frond towards the 

 sterile has taken place from the base towards the tip, in the pinnae 

 \ hat are partly fertile the change is in the reverse order, that is from 

 the tip towards the base. Usually after the discharge of the spores 

 the fertile fronds wither and finally disappear, but in this case they 

 have not withered, as have the other fertile fronds, but mantam 

 their normal upright habit instead of curving backward. — Isaac C. 

 Marthstdale, Camden, N. J. 



The Action of Acids on Cellulose and Starch-grains.— 



In the Botanical Gazette for May a discrepancy is shown be- 

 tween a statement made in Sachs 1 Text-book of Botany and some 

 facts found bv experiment, and an explanation is asked. It refers 

 to the action of acids on cellulose. In the fourth revised edition of 

 Sachs 1 Lehrbuch der Botanik (Leipzig, 1874.) this discrepancy does 

 not exist. The translation by Bennett and Dyer was based on the 

 third edition, and it is probable some change was made by the au- 

 thor in the later work. But not possessing the translation nor 

 any edition earlier than the fourth, I cannot compare them. The 

 accuracy of the translation may be assumed from the competency 

 of those who made it. The same subject is evidently treated in the 

 fourth edition, page 640, where a paragraph is found referring to 

 the action of acids on cellulose and starch-grains, and a figure of 

 those of Hoija carnosa under the influence of this treatment is in- 

 serted. A translation of the passage is given below.. It will be 

 -seen that the per cent, of dilution is not stated, but is presumably 

 .somewhere near that found, necessary by the experiments in Pur- 

 due University. It is with the second mode of treatment that the 

 violent action is said to occur. The first adjective might be rendered 

 "violent," but hardly means this when compared with the second, 

 where the primary meaning is violent. 



"Acids (especially sulphuric), greatly diluted with water, cause a 

 stronger swelling (eine starkere Quellung) of starch-grains and cel- 

 lulose than pure water, without however destroying their organiza- 

 tion. After the acid is removed by washing they return to their for- 

 mer condition. But at a higher concentration (bei hoeherer Concen- 

 tration) the acid produces a violent swelling (eine heftige Quellung) 

 of starch-grains and cellulose; they are changed into a pasty state: 

 the protoplasm coagulates just as it does at a higher temperature. 

 Concentrated sulphuric acid finally destroys their molecular struc- 

 ture completely, causing a chemical change of substance; they are 

 liquefied."— E." J. Hill, Enghwood, III. 



