464 Descendenz u. Hybriden. — Morphologie etc. — Piiysiologie. 



constater que pendant leurs cinq premieres annöes d'existence 

 les individus descendant de graines de diverses provenances, 

 sp^cialement en ce qui concerne l'altitude, ont h^ritd et 

 conserv^ dans les stations nouvelles oü ils ont et^ 

 cultiv^s les pa r ticularites mor phol ogiques, anato- 

 miques et biologiques acquises par leurs parents 

 dans leurs stations originelles. II y a tout Heu 

 d'espdrer que la suite de ses recherches permettra ä Engler 

 de confirmer ces premiers resultats et specialement la con- 

 clusion pratique qui resume son travail, ä savoir que „pour la 

 culture d'essences spontanees, il faut recueillir les; graines dans 

 la r^gion meme oij elles doivent etre employees, et si possible, 

 dans des stations dont les conditions ecologiques oifrent le 

 plus d'analogies avec Celles du Heu oü elles seront employees". 



Paul Jaccard. 



Mc. Callum, W. B., Regeneration in Plauts. I. (Bot. Gaz. 

 Vol. XL. Aug. 1905. p. 97 — 120. 14 Hg. in text.) 



In introduction discusses general question of regeneration. 

 Classifies the possible factors connected with regeneration 

 phenomena under the following heads: 1) wound Stimulus; 2) 

 disturbance in nutrition; 3) changes in water current; 4) accu- 

 mulation at certain places of deHnite formative substances; 5) 

 correlation; 6) relative age and maturity of the different parts 

 of a member; 7) growth tensions. 



This paper is concerned with numbers two and three of 

 the above, and in a series of experiments, mostly upon 

 Phaseollis these topics are discussed. As to disturbance of 

 nutrition, concludes that by the experimental evidence given, 

 there is no necessity of increase of the nutritive conditions to 

 cause regeneration. With some thirty experiments the author 

 has investigated the question of disturbance in water content. 

 Finds, that in Phaseoliis, at least, the increase of water at any 

 point along the stem is not of itself the Stimulus for the for- 

 mation of roots, but that root primordia may be laid down 

 when the cells contain less than the normal water supply. The 

 subsequent development, however, will depend upon a proper 

 supply of externa! water. From some other experiments con- 

 cludes that while in cases like Salix there can be no doubt 

 that water will start the development of roots, the same result 

 can be brought about by other means, even when the cells are 

 losing water. „In the greater majority of instances where 

 regeneration occurs, however, it cannot be due to any distur- 

 bance in the amount of water present in the parts concerned." 



H. M. Richards (New York). 



Caldwell, J. S., The Effects of Toxic Agents Upon 

 the Action of Bromelin. (Bot. Gaz. Vol. XXXIX. 

 June 1905. p. 407—419.) 



Extracted enzyme from Pineapples of varying ripeness and 



found that in general the product was markedly more active 



