730 5. Entwicklungslehre. 



when all these nutrient elements were present and was best in those mixtures which 

 contained between 10 and 30 per cent phosphate; between 30 and 60 per cent 

 nitrate; and between 30 and 60 per cent potash. The growth in the Solutions 

 coutaining all three constituents was much greater than in Solutions containing 

 two constituents, the Solutions containing the Single constituents giving the 

 least growth. The concentration differences noticed in the Solutions were also 

 very striking, the greater reduction in concentration occurring where the 

 greatest growth occurred. The change in the ratios of the Solutions and the 

 ratios of the materials that were removed from the Solutions sbowed that where 

 the greatest growth occurred the Solutions suffered the least change in ratio, 

 although the greatest change in concentration occurred. The more the ratios 

 in these Solutions differed from the ratios in which the greatest growth oc- 

 curred, the more were the Solutions altered in the course of the experiment, 

 the tendency in all cases seeming to be for the plant to remove from any and 

 all of these Solutions the ratio which normally existed where greatest growth 

 occurred, but was hindered in doing so by the unbalanced condition of the 

 Solution. The results show that the higher the amount of one constituent 

 present in the Solution, the more does the culture growing in that Solution 

 take up this constituent, although it does not seem able to use this additional 

 amount economically. In the very early periods the ratio of phosphate ab- 

 sorption is low and the potash absorption high, although in final growth the 

 greater response is obtained with nitrate, indicating relatively low phosphate 

 requirement and high potash requirement of the seedling plant'. 



Pearl (Orono). 



1584) Bullen, 0. E., On an Example of Posterior Dichotomy in an 

 Aylesbury Duckling. 



(Proc. Zool. Soc. 3. p. 66G— 669. 2 figs. 1910.) 



Describes a duckling which had in addition to the normal legs a dicho- 

 tomised third leg in a median ventral position. The pelvis was reduplicated, 

 the accessory femur trifid at its distal end; three tibio-tarsi were present, bear- 

 ing two well-developed accessory limbs, the middle tibio-tarsus bearing only 

 a short rudiment of a tibio-tarsus. The feet of the accessory limbs were 

 imperfect. Another individual showing dichotomy is said to have hatched 

 from the same batch of eggs. Doncaster (Cambridge). 



1585) Berg, R. (Physiologisch-chemisches Labor. [Dr. Lab mann, Weißer 

 Hirsch b. Dresden]), Über den Mechanismus der Beeinflussung 

 der körperlichen Entwicklung durch die Wasserhärte. 



(Biochem. Ztschr. 27,3. p. 204-222. 1910.) 

 Die Ansicht vom Einfluß der Trinkwasserharte auf den menschlichen Orga- 

 nismus stammt von Rose. Auf dem Umweg über die Bodenerzeugnisse könnte 

 die Wasserhärte durch Zufuhr als Trinkwasser, Kaffee, Bier und Suppe mög- 

 lich sein. Diese Vorstellung wird in mancher Beziehung richtiggestellt. Zwi- 

 schen Trinkwasserhärte und der Zusammensetzung der Roggenasche, den Kar- 

 toffeln, der Gemüse und Obstsorten bestehen keine Beziehungen. Ferner fehlen 

 Beziehungen zwischen dem Magnesia- und dem Phosphorsäuregehalt in Kar- 

 toffeln und Roggen gegenüber der Ackerkrume; ebenso zwischen Gehalt des 

 Eigelbs an Mineralwasserstoffen gegenüber dem Gehalt das Bodens daran. Ist 

 also die Trinkwasserhärte nicht von Einfluß auf die Zusammensetzung der Nah- 

 rungsmittel während ihres Wachstums, so kann sie es sein auf die Zubereitung 

 der Speisen. Es werden daher Kartoffeln und Gemüse mit Wasser verschie- 

 dener Härte gekocht und es ergibt sich, daß Kalk und Magnesia in den Vege- 

 tabilien wenigstens zum größten Teil in löslicher Form enthalten sein müssen, 



