824 



SCIENCE. 



[N. S. Vol. XIX. No. 491. 



abandoned, simply on account of the contin- 

 ued trouble from alga3. The direct result of 

 the presence of alga3 in serious cases is that 

 the water acquires a very disagreeable odor 

 and taste which may resemble that of decay- 

 ing wood or has what is described as a ' fishy ' 

 smell and taste. Often this odor and this 

 taste are not due to the decomposition of the 

 plants but are caused by small drops of oil 

 secreted by certain of the algse. 



Up to the present time no practicable rem- 

 edy has been found for this trouble which is 

 capable of general application. Double filtra- 

 tion, covering the reservoir, the removal of all 

 organic matter and similar expedients have all 

 been tried, and in some cases proved nearly or 

 quite eflicient, but such means are usually too 

 expensive or for some other reason are imprac- 

 ticable. It has been shown by experiment, 

 however, that it is quite feasible , to treat in- 

 fected reservoirs with copper sulphate in such 

 quantities as to give a solution varying from 

 one part in a million down to one part in 

 500 million. The former strength is not con- 

 sidered harmful even as a constant beverage, 

 and the latter dilution appears to be effective 

 in disposing of most algse under ordinary con- 

 ditions. In water containing any appreciable 

 amount of lime or organic matter, the copper 

 is soon precipitated out, so that the danger of 

 harmful overdosing is still further prevented. 



The speaker deprecated the extravagant 

 statements that have recently been made in 

 the daily papers regarding the efficacy of this 

 copper treatment in ridding water supplies of 

 certain pathogenic bacteria, such as the germs 

 of typhoid and cholera. In his opinion the 

 present indications are that where no other 

 remedies can be applied to prevent or remove 

 bacterial, infection this may be accomplished 

 by treatment with copper. It is in no way 

 designed to replace slow sand or other effec- 

 tive filtration methods now in use, but it is 

 believed may be of some service where such 

 systems are not installed. 



Mr. L. L. Harter, of the Department of 

 Agriculture, then spoke on the subject, ' Va- 

 rietal Differences in Resistance to Toxic Salts.' 

 The speaker outlined some experiments that 

 he has recently undertaken with a view of de- 



termining whether or not varieties of the same 

 species differ in' their resistance to toxic 

 salt solution. He has conducted the work 

 with wheat varieties obtained from various 

 sources and which show great diversity of cli- 

 matic and soil conditions. 

 , He found that it required a solution of 

 sodium carbonate three times as concentrated 

 to kill a Kansas or Russian variety as it did 

 one from Michigan. The limits in sodium 

 chloride varied from .045 to .055 of a normal 

 solution, and of sodium bicarbonate from .025 

 to .03. He further showed that the Michigan 

 and Russian varieties are two and one half 

 and two times respectively more resistant in 

 magnesium chloride than one obtained from 

 Turkestan. Almost as great a variation was 

 obtained with the Michigan and Kansas varie- 

 ties over the one from Turkestan, requiring 

 in both cases twice the concelitration of mag- 

 nesium sulphate to kill the root tips. 



Carl S. Scofield, 

 Eecording Secretary. 



THE TOEREY BOTANICAL CLUB. 



The meeting of Tuesday, March 8, 1904, 

 was held at the College of Pharmacy, with 

 Vice-president Rusby in the chair; there were 

 seventeen persons present. The minutes of 

 the preceding meeting were read and approved. 



The first paper on the scientific program 

 was by Professor Francis E. Lloyd on ' Recent 

 Investigations on the Pollen-tube,' and was 

 an interesting exposition of the parallel re- 

 sults of Longo's investigations on the behavior 

 of the pollen-tube in Cucurbitaceae and Pro- 

 fessor Lloyd's work on Eubiacese. 



Longo finds that in Cucurhita Pepo L., the 

 ovary is provided with a special conductive 

 tissue reaching to the neck of the fiask-shaped 

 nucellus by means of which the pollen-tube 

 follows a completely intercellular course from 

 stigma to embryo-sac. In other species of 

 Cucurhita and in Citrullus vulgaris the neck 

 of the nucellus is not long enough to reach to 

 the conductive tissue, so that for a short dis- 

 tance the tube must move through a cavity. 

 On reaching the neck of the nucellus, the 

 pollen-tube forms a bulla that produces lateral 

 outgrowths which Longo believes are for the 



