466 Miscellaneous. 



into the open water. In these insects respiration appears to take 

 })lace in the usual way, through spiracles. A common house-fly, 

 placed under water, ceased to move in half an hour, while the speci- 

 mens now referred to lived under water for several hours without 

 suffering any apparent inconvenience, and one was observed to be 

 quite lively after having been so placed at least twelve hours, which, 

 it was stated from further observation, is probably about the limit 

 of their endurance. Drawings of the two insects accompanied the 

 paper, which also contained an account of their organization. 



On the Appearances of Cotton-fibre during Solution and Dis- 

 integration. By Charles O'Neill, F.C.S. 



These experiments referred to the application of Schweizer's sol- 

 vent. Two strengths were used : the weaker contained oxide of 

 copper equal to 4*3 grains metal per 1000, and 4/ grs. dry ammonia; 

 the stronger contained 15*4 grs. metal and 77 grs. dry ammonia per 

 1000. The latter is about the most concentrated solution which can 

 be made. Referring to the researches of Payen, Fremy, Peligot, 

 Schlossberger, and others who have employed this solvent, the au- 

 thor said the only experimenter who seemed to have worked in the 

 same direction with himself, and that apparently only to a small 

 extent, was Dr. Cramer, whose paper he had only been able to see 

 in a translation appended as a note to a memoir of M. Payen in 

 *Compte3 Rendus,' vol. xlviii. p. 319. 



Mr. O'Neill considers that cotton exhibits, under the action of 

 this solvent (1) an external membrane distinct from the true cell- 

 wall or cellulose matter; (2) spiral vessels situated either in or out- 

 side the external membrane ; (3) the true cell-wall or cellulose ; and 

 (4) an inner medullary matter. The external membrane is insoluble 

 in the solvent, and may be obtained in short hollow cylinders by 

 first acting upon the cotton with the dilute solvent so as to gradually 

 remove the cellulose, and then dissolving all soluble matters by the 

 strong solvent. If the strong solution is first applied, the extra- 

 ordinary dilatation of the cellulose bursts the external membrane, and 

 reduces it to such a state of tenuity that it is invisible. This mem- 

 brane is very elastic, appears to be quite impermeable to the solvent, 

 and, when free from fissures, protects the enclosed matter from its 

 action. It is not seen in cotton which has been submitted to the 

 action of bleaching agents, being either chemically altered or, what 

 is most probable, entirely removed. 



The spiral vessels are unmistakeably apparent, running round the 

 fibre in more or less close spirals, sometimes single, sometimes double 

 and parallel, and at other times double and in opposite directions, or 

 again seemingly wound close and tight round the cylinder. They 

 are well seen in the spherical swellings or beads, but are prominent 

 at the points of strangulation of long ovals formed when the ends 

 of the fibres are held tightly. They collect in a close mass, forming 

 a ligature, and are frequently ruptured, the ends projecting from the 

 side of the fibre. 



