100 



But, aside from the interest attached to tliis new genus of the Volmciniae from 

 the botanical point of view, it may be found to have important relations to odors 

 and tastes in water supplies, when it will become the enemy of engineers and 

 water commissioners, as other members of this group have done l)eIore. For ex- 

 ample, Votvox ylobator has caused much trouble in Rochester, X. Y., by imi)arting 

 a disagreeable fishy odor to the city water supply, and in Massachusetts Puudorina 

 and Eudorina have caused similar troubles on a smaller scale. Pt-oiiorina. com- 

 ing as it does between Volvox and Eudorina in the classification, may be looked 

 upon with suspicion in this respect, if it ever infects a water supply in a sufficient 

 quantity. On account of the filthy condition of the canal water in which it was 

 found in Lafayette, and the number of other forms growing witli it, ni> idea could 

 be formed as to the nature of the odor, if any, of Pleodorina. 



Forms of Xanthium C'axadense and X. .strumakium. Bv .J. C Arthir. 

 In the absence of tlie author the outline of the paper was presented by Mr. 

 Wm. Stuart and photographs of the two species were shown. The species in their 

 most typical forms diSier widely in the outline of the leaf and cliaracter and size 

 of the burs. X. Canadense has a flowing sub-entire outline to llie leaf, and large, 

 strongly hispid fruit covered thickly with prickles, while A', stiumuritiin has den- 

 tate leaves and smaller glabrous fruit with fewer prickles. All gradation^ exist 

 between tlie two types, due possibly to hybridization. 



X'oTE.s ON Wood Shrinkage. By M. J. Golden. 

 The increase or diminution in size of a |)iece of wood, due to its pos.session of 

 a greater or less amount of moisture, is well known, as is a\so the tact that this 

 change in size may be accompanied by the expenditure of a great ileal nf force. 

 If an unseasoned piece of wood has two sides fastened rigidly so that it can not 

 shrink across the grain, and then be exposed to a current of comparatively dry 

 air, it will very soon break, the break being in the tlirection of the leugtli of the 

 cells of which the wood fibers are composed; or if a piece of dry wood be con- 

 fined rigidly to jjrevent any increa^'e in size and then be saturated with moisture, 

 it will tend to swell and the force will be sufficient to crush the fibers where tiiey 

 are in contact with whatever confines them. 



