216 



BOOKS AND CURRENT LITERATURE 



in a measure, disagree concerning the character of the abciss layer and 

 maintain that it is not so simple as represented by the author. This 

 howelver is a minor point. 



The remaining portion of the work, which concerns genetics, must 

 remain for those directly interested. The lack of final generalization 

 desirable for the non-specialist does not deter from its value. It repre- 

 sents an immense amount of detailed work which, carried forward by 

 the author, must certainly lead to important scientific and economic 

 results. He says trenchantly, however, by way of a practical generali- 

 zation from the observed facts of inheritance, that the agriculturist of 

 the near future will not choose his seed and then look for his land, but, 

 having chosen his land will "manufacture" a cotton plant to suit it. 



In concluding, it may be stated that the hypothesis, earlier favorably 

 entertained, that the deterioration of Egyptian cotton is due to the rise 

 of the water table, is in the condition little short of a proven case and 

 that it remains to modify agricultural methods in order to bring the 

 crop back to its proper standard. — F. E. L. 



Algae and Dissolved Gases. — The present contribution^ to this 

 interesting problem is based upon results obtained both in the field and 

 in the laboratory. Serial observations on a lagoon in the Missouri 

 Botanical Garden in 1911 showed that the rise in the number of algae 

 in June, which reached the "water bloom" stage in July, was accom- 

 panied by a gradual increase in the quantity of dissolved oxygen, the 

 maximum amount being well above the saturation point. Correlated 

 with this was a decrease in the carbon dioxide. In the process of photo- 

 synthesis the algae consumed all of the free and enough of the half» 

 bound carbon dioxide to give the water an alkalinity equivalent to 

 7 cc. of this gas per liter. The water then remained alkaline until the 

 autumn rains began in September. Owing to the unfavorable condi- 

 tions after this time, the oxygen decreased in amount and the carbon 

 dioxide increased. By December the former had declined to 3 cc. and 

 the latter had risen to 10 cc. of free carbon dioxide per liter of water. 



In laboratory experiments it was found that algae grown in culture 

 media containing an excess of oxygen had a brighter color than the 

 control cultures, or than those grown in media containing an excess of 

 free carbon dioxide. The carbon dioxide cultures showed chiefly coeno- 



1 Chambers, C. O., The relation of algae to dissolved oxygen and carbon dioxide, 

 with special reference to the carbonates. Twenty-third Ann. Rept. Mo. Bot. • 

 Garden, pp. 171-207, 1912. 



