Physiologie. 465 



in alkaline than in acid media. As this differs from previously 

 recorded results, this matter of tiie action in alkaline media 

 was carefully investigated. Arrives at the conclusion that tiiere 

 may be in reality two enzymes present in the extract, one 

 active in acid, the other in alkaline Solutions. A large number 

 of poisonous salts were used and their action upon the activity 

 of the enzyme may be summarized as follows. The action of 

 the enzyme is inhibited by the poisonous substance, the con- 

 centration varying with the nature of the salt. The inhibition 

 takes place at a lower concentration in acid, than in alkaline 

 media. The effects of poisons vary with the purity of the pre- 

 paration, even slight impurities of proteid matter render the 

 necessary concentration for toxic action much higher. Despite 

 this, however, the relative toxicity of various salts remains the 

 same. Also finds that bromelin, when prepared in a relativly 

 pure condition is not at all autodigestive, but apparently requires 

 the presence of proteid from the juice of the plant. 



H. M. Richards (New York). 



Dean, A. L., On Proteolytic Enzymes. II. (Bot. Gaz. 

 Vol. XL. p. 121—134. Aug. 1905.) 



A continuation of a paper, by the same author, which has 

 already been noticed. In his conclusion the author points out 

 that the proteolysis which takes place in the seeds of Phaseolus 

 vulgaris during germination, might be carried out in three ways. 

 First by the action of a tryptic enzyme; second by the combi- 

 ned action of the protoplasm and of an enzyme which is not 

 capable, by itself, of carrying on the whole process ; or third, 

 by the action of the protoplasm alone. The first is to be thrown 

 out in this case, as no proteolytic enzyme was found capable 

 of digesting the proteids of the seed. As to the second pos- 

 sibility, there has been found an ereptic enzyme which is able 

 to digest the proteoses resulting from the partial hydrolysis of 

 the seed proteids. Consequently it is suggested that it is pro- 

 toplasm, itself, which initiates the digestion, while the ereptase 

 completes the process. It is admitted there is a possibility that 

 the complete hydrolysis is carried out by the protoplasm itself, 

 but the very presence of the active ereptase at a certain stage 

 leads to the inference that it must have some part in the pro- 

 cess of cleavage. The author further remarks that it is quite 

 conceivable that the cleavage of protoplasmic proteids, which 

 is supposedly an important part in the activity of the living cell, 

 may be effected in different ways in different cells. 



H. M. Richards (New York). 



Meyer, A., Orientierende Untersuchungen über Ver- 

 breitung, Morphologie und Chemie des Volutin s. 

 (Bot. Ztg. Bd. LXII. I. p. 113—152. Taf. V. 1904.) 



In der Classe der Thallopliyten entdeckte Verf. eine Körper- 

 gruppe, die wahrscheinlich in ihrer physiologischen Bedeutung 



Botan. Centralblatt. Bd. XCIX. 1905 30 



