September 27, 1895.] 



SCIENCE. 



403 



eases Due to Fusarium, by Eewin F. Smith, 

 Washington, D. C. The author reviewed 

 the work of last year and gave the results 

 of investigations confirming previous state- 

 ments regarding the nature and cause of 

 watermelon wilt. The discovery of two 

 additional stages of the wilt fungus were 

 noted, and evidence was brought forward to 

 show the great vitality of the fungus. 

 Wilt diseases caused by Fusarium have been 

 recently found in a number of other plants, 

 notably sweet potato, cabbage, and cowpeas. 

 On the last-mentioned plant a new Nectriella 

 was found, and the evidence shows that the 

 conidia so abundant outside and inside of 

 the plant are but forms of this Ascomycete. 

 3. Observations on the Development of Uncinula 

 spiralis B. & C, by B. T. Galloway, Washing- 

 ton, D. C. The author first called attention 

 to a paper presented before the Association 

 in 1890, in which it was shown by artificial 

 cultures that the forms of Uncinula spiralis 

 found on Vitis and Ampelopsis are identi- 

 cal. The development of the fungus was 

 then discussed, especial attention being- 

 called to the manner in which the parasite 

 passes the winter. It was shown that the 

 first material change in the fungus after the 

 leaves have fallen is the disappearance of 

 the perithecial appendages. Observations 

 made from time to time brought out the 

 fact that there was no germination of as- 

 cospores before January. Through the 

 months of January and February the asco- 

 spores were successfully germinated by 

 keeping perithecia, which had been out all 

 winter, for several weeks in moist chambers. 

 The asci were ejected from the perithecia 

 with considerable force, and in most cases 

 collapsed as soon as free. Only a compara- 

 tively small number of asci and ascospores 

 remained perfect, and such of the latter 

 as did not break up commenced to germi- 

 nate within four or five hours after their 

 escape from the ascus. Attempts were 

 made to obtain the fungus on Vitis and 



Ampelopsis by sowing ascospores, but this 

 work was wholly negative. . 



4. The Effect of Sudden Changes of Turgor 

 and of Temperature on Ch-owth, by Rodney 

 H. Tbue, Madison, Wis. In the absence of 

 the author, this paper also was read by Prof. 

 Barnes. The author claims that growth and 

 turgor pressure have no direct proportional 

 relation, and in proof of this shows the vari- 

 ation in growth when a radicle is suddenly 

 transferred from water to a one per cent, 

 solution of KNO3 or vice versa, or when it 

 is accommodated to these media by a stay 

 of two or three days before the ti-ansfer is 

 made. He attributes retardation to the 

 irritable qualities of the plant, and in sub- 

 stantiation of this discusses the fact that 

 when change of medium produces a very 

 material increase of turgor pressure the rate 

 of gi'owth usual for both media mentioned 

 falls below the normal. He found changes 

 of temperature to affect growth in about 

 the same way as changes of turgor, the re- 

 tardation period in this case depending 

 upon length of time between extremes and 

 length of time spent at the lower limit when 

 the plant is transferred to a normal range. 

 The author's conclusion is that sudden 

 changes in turgor pressure or surrounding- 

 temperature act as a shock to the irritable 

 organisms and cause a pronounced retarda- 

 tion of growth . 



5. Recording Apparatus for the Study of 

 Transpiration of Plants, by Albert F. Woods, 

 Washington, D. C. Attention was first 

 called by the author to the fact that the 

 direct method of weighing the plant is the 

 most satisfactory one of determining the 

 amount of water evaporated during a given 

 period. Various automatic devices for ac- 

 complishing this object have been described 

 and used. The apparatus in question is 

 a modification of Marvin's recording rain 

 and snow gauge, and is designed to register 

 automatically the loss of water through any 

 given period. It is constructed so as to 



