III. 6 ATMOSPHERIC PRESSURE 115 



J. LOEB. Untersuchungen iiber die physiologischen Wirkungen des 

 Sauerstoffmangels, Pfluger's Arch. Ixii, 1896. 



P. MITROPHANOW. Einfluss der veranderten Respirationsbedingungen 

 auf die erste Entwickelung des Hiihnerembryos, Arch. Ent. Mech. x, 1900. 



R. POTT. Versuche uber die Respiration des Huhner-Embryo in einer 

 Sauerstoffatmosphare, Pfluger's Arch, xxxi, 1883. 



R. POTT und W. PREYER. Ueber den Gaswechsel und die chemischen 

 Veranderungen des Huhnereies wahrend der Bebrutung, Pfluger's Arch. 

 xxvii, 1882. 



W. PREYER. Spezielle Physiologic des Embryo, Leipzig, 1885. 



A. RAUBER. Ueber den Einfluss der Temperatur, des atmospharis-chen 

 Di-uckes und verschiedener Stoffe auf die Entwicklung thierischer Eier, 

 S.-B. Naturf. Oes. Leipzig, x, 1883. 



H. SAMASSA. Ueber die ausseren Entwicklungsbedingungen der Eier 

 von Rana temporaries, Verh. Deittsch. Zool. Ges. vi, 1896. 



7. OSMOTIC PRESSURE. THE K6LE OF WATER 

 IN GROWTH 



That growth seems to depend in many cases on the absorption 

 of water or a watery fluid in the swelling of the Echinoderm 

 blastula, for example, or the enlargement of the Mammalian 

 blastocyst has been noticed by several observers; in a few 

 instances experimental proof has been given of the relation 

 between the two. 



Although, as is very well known, the Hen's egg loses weight 

 daily throughout incubation by loss of water, this loss is due 

 almost entirely to the slow evaporation of the albumen, and 

 a humid atmosphere is necessary for development, as Pott and 

 Preyer have found. Fere's experiments with eggs incubated 

 in desiccators demonstrated, during later stages, a slight re- 

 tardation accompanied by abnormalities and a high death-rate ; 

 in earlier stages, up to about the fourth day, there was on the 

 contrary an acceleration of development. 



Davenport has shown for tadpoles of various Amphibia (Am- 

 blystoma, Toads, Frogs) that increase in weight is very largely 

 due to increase in weight of water. Known numbers of tad- 

 poles, from which superficial water had first been carefully 

 removed, were placed over sulphuric acid in a desiccator. Re- 



i 2 



