INVERTEBEA.TA, CRYPTOGAMIA, MICROSCOPY, ETC. 595 



Starch-transforming Ferments.*— Substances whicli possess the 

 power of producing fermentation in starch, i.e. of transforming it into 

 sugar, were found by Barauetzky in dormant and germinating seeds 

 which contain starch, in germinating starchy tubers, in stems and 

 leaves, and also in receptacles for reserve materials which contain no 

 starch, as in germinating turnips and carrots. The result was the 

 same whether the plants grew in the light or in dark. The product 

 of the fermentation of starch was determined by quantitative analysis 

 to consist of a mixture of glucose and maltose, the analysis being 

 made as soon as the starch reaction with iodine failed. The forma- 

 tion of these sugars was hindered by elevation of the temperature. 

 From the similarity of its action, Baranetzky concluded the identity 

 of the ferment obtained from different plants. He believes, in accord- 

 ance with Payen, that the chemical process which takes place is, that 

 dextrin is first formed, and subsequently sugar by absorption of water ; 

 not as O'Sullivan thinks, a division of the molecule of starch into 

 dextrin and sugar. The granulose in the starch-grains is first acted 

 on, then the cellulose (farinose). The action takes place with very 

 different rapidity in different starch-grains ; those of wheat and 

 buckwheat ferment speedily ; those of rice and potato only with 

 great difficulty ; and this is not altogether dependent on the relative 

 proportion of the two ingredients in the starch ; since the grains of 

 the scarlet-runner, which leave behind a tough skeleton of farinose, 

 are acted upon very rapidly, those of the horse-chestnut only with 

 great difficulty, although they leave but a very delicate skeleton. The 

 actual ferment he believes to be an albuminoid, and its action to be 

 dependent on the presence of oxygen. The distribution of this 

 ferment in the vegetable kingdom he concludes to be very general. 



Krauch differs from Baranetzky in maintaining diastase to be a 

 definite chemical compound, which he has detected in onions and the 

 seeds of the gourd. He agrees with that writer in regarding diastase 

 as a widely distributed substance in organs which contain starch, and 

 generally in proportion to the amount of starch. It sometimes exists 

 in the organ while in a dormant state ; sometimes it is only found 

 when active growth begins. 



Tannin in Vegetable Cells-f — J. B. Schiitzler records the results 

 of some experiments on this subject. The test emjjloyed was the 

 action on ferric chloride or some other iron salt, which causes the 

 protoplasm to contract, kills it, and then produces a black precipitate 

 when tannin or a substance belonging to the same series is present. 

 This was first observed in the glands which cause the oily feel of the 

 upper surface of the leaves of Paulownia impcrialis, and subsequently 

 in the leaves of Prunus Laurocerasus. Tannin was also found in 

 fresh-water algae belonging to the genera Vaucheria, Sjnrogyra, Con- 

 ferva, &c., in sufficient quantities for a good ink to be prepared from the 



* ' Die sfarkeumbildenden Fermeute in der Pflauzen,' von Dr. J. Baranetzky, 

 Leipzig, 1878. ' Beitrage zur Kenntniss der uugeformten FL-rmeute in der Pflun- 

 zen,' von K. Krauch, Erlangeu, 1878. See ' Bot. Zeit.,' xxxvii. (1879) p. 156. 



t 'Arch. Sci. Phys. et Nat.,' i. (1879) p. 344. 



