400 Angewandte Botanik. — Biographie. — Personalnachrichten. 



bable yield of each plot on the supposition that they have all been 

 planted with a hypothetical variety whose mean yield is the same 

 as the observed means of the field. 



This „calculated" yield may then be used as a basis for deter- 

 ming a correction factor. If the calculated yield of a given plot is 

 above the mean of the field it must be taken that the soil of this 

 plot is better than the average of the field and a corresponding 

 amount must be deducted from the observed yield. Likewise, if 

 the calculated yield is below the average, a proportional amount 

 must be added to the observed yield in order to make the plots 

 comparable. 



Still more comparable results will be obtained if the correction 

 factors are based upon the percentage of the mean rather than 

 upon the absolute figures. 



Tests of the efficiency of this method by means of the measure 

 of soil heterogeneity proposed by Harris, show in all cases a very 

 marked reduction in the amount of heterogeneity when the cor- 

 rected figures are used. When tested on the writers own experi- 

 mental plots, this method leads to results which from other evi- 

 dence, they have reason to believe, more nearly represent the 

 truth than do the uncorrected yields. 



It is realized that this method is not ideal and does not obviate 

 all the difificulties connected with soil differences in plot experiments. 

 It is hoped that this method may prove useful in certain kinds of 

 plot experiments and that it may lead to further study of this 

 Problem. M. J. Sirks (Wageningen). 



Chodat, R., Philippe van Tieghem 1839 — 1914. (Ben 

 Deutsch. Bot. Ges. XXXIII. p. (5)— (24). 1915 [1916].) 



Die wissenschaftlichen Arbeiten des Verstorbenen können ein- 

 geteilt werden in mykologisch-physiologische, physiologische, ana- 

 tomische und in solche über die allgemeine Systematik der höheren 

 Pflanzen. Hervorzuheben sind: Wirkung der Schimmelpilze als Er- 

 reger der Gerbstoffgärung, Studien über den Bacillus amylobacter 

 (van Tieghem ist da Vorläufer der botanischen Enzymologie), 

 Reinkulturen der Mucorineen, Dextrosegärung des Leuconostoc 

 mesenteriodes, anaerobiotische Atmung der Pflanzengewebe unter 

 Bildung von Aeth5^1alkohol, Versuche über die Teilbarkeit der 

 pflanzlichen Embryonen und deren Regeneration, topographische 

 Pflanzenanatomie, die bekannten Arbeiten über die Wurzel. 

 Stelär-Theorie, Aufstellung eines neuen Pflanzensystems. Er prägte 

 seinen Mitarbeiten seinen durchdringenden, durchwegs originellen 

 Geist bei den wissenschaftlichen Untersuchungen auf. — Es folgt 

 eine kurze Biographie. Malouschek ;Wien). 



Personalnaeliriehten. 



Died: at the age of 47 years Dr. E. A. Newell Arber, de- 

 monstrator in palaeobotany at the University of Cambridge. — 

 Maurice de Vilmorin Paris. 



A.ii8a;eg:elt>eii : 18 .Tiiiii 1018. 



Verlag von Gustav Fischer in Jena. 

 Buchdruckerei A. W. Süthoff in Leidea. 



