343 



50° C, the vascular bundles will first take a deep blue colour, which shows thal there 

 the emulsine is the most accumulated. Then the parenchyma around thcm grows blue, 

 and finally the more peripheric parenchyma. This points out that the emulsine is now- 

 here wholly absent is accumulated about the coiifines of the central-cylinder, which 

 becomes distinctly visible by this experiment '). 



A rather great number of other plants examined for indigo-enzymes have all 

 given negative results *). 



Neither is indican decomposed by sections of branches or leaves of apricots, 

 pears, apples, peaches, while in the kernels of the fruits of these species a feebly 

 decomposing emulsine is found. 



Malt, malt-diastase. pancreas, papayotine, pepsine and saliva are inactive; like- 

 wise mustard-seed and myrosine prepared from Tropaeolum majus. 



(llucase, from maize does not decompose indican, which is the more noteworthlv 

 as amygdaline is decomposed by it. 



4. üccompositioii of Indican by Microbes in ^eneral. 



Mr. Molisch has drawn attention to the fact, that various species of microbes 

 give rise to indigo-formation from indican and that others do not, whicli mav be 

 rendered useful for differential diagnosis. He experimented with the decoct of Poly- 

 gottuni tinctorium or Indigofera mixed with agar or gelatine, pouring it out to plates 

 and using these as a sulid nutriënt. .Aerobics anil temporary anaerobics from the 

 soil or from canal water sown out on it will develop, and in and around the colonies 

 which split the indican, indigo-blue will separate out in microscopic lumps or globules 

 which often show crystal structure. The »indican microbes« are in this wav elegantly 

 distinguished as pigment-microbes among the non-decomposers '). 



') Nearly the same has been found by Johannsen, whn ixanmu-d the deconiposi- 

 tion of amygdaline with separate parts of the sccdlobes. (.-\nn. Sci. Nat. Botan. Série 7, 

 T. 6, p. 118, 1887.) 



') So I could nut tind indigo-enzymes in: Indigofera dosua. Polygonunt [•ersicaria, 

 P. aviculare, I'. iagopynini, F. bistorta, F', sacclialinense, Trifolium repens, T. pratense. 

 Medicago sativa, Lotus corniculata, l'isHnt satixnun, Vicia faba, Robinia pseiidoacacia, 

 Baptisia australis, Meldotus caeruleus, Spiraea ülipendula. S. ulmaria. Rubia tinctorium, 

 Asperula odorata, Solanuin tuberosum, Amsonia salicifolia. Asclepias cornuti. Scorcunera 

 hispanica, Linaria vidgaris. Stellaria bolostea. Cochlcaria armoracia, Hrassicca oleracea, Isatis 

 tinctoria, Iris gernianica. 



") Sitzungsber. der .-Kkad. d. Wiss. zu Wien. Math. Xaturw. Clas>e. Bd. 107, p. 758, 

 1808. Mr. Molisch enumerates the ffillowing species as decomposing indican: Bacillus 

 anthracis, B. prodigiosus, Streptothrix odorifera. S. dicliotoina, Sarcine lutea. l'enicillium sp. 

 and Mucor nnicedo; as non-decomposing: Streptococcus pyogenes, Staphylococcus pyogenes 

 aureus, Bacillus subtilis, B. coli communis. B. fluorescens liquefaciens. B. inegatlierium and 

 pressed yeast. Mr. van Hasselt and I saw no dccomposition uith Acetobacter aceti, 



A. ranscens, Bacillus cyaneus, B. cyanogenus, B. pyocyaneus, B. diastaticiis, B. prodigiosus, 



B. pseudotuberculosis. Many spore-forming bacteria, such as ö. subtilis, B. megathcrium, 

 B. pulcher, B. mesentericus and others somctimes decompose and somctimes do not. 

 Furthcr there is no indican splitting by beeryeast (Saccharomyces cerex'isiae), winc-yeast 

 {S. cllipsoideus), presscd-yeast (S. panis), S. mycoderma, S. passutarum, S. uTaruin, Schi:o- 

 saccbaromyes octosporus, S.pombe and by the following moulds; Aspergillus niger, A.oryzae, 

 Amylomyces rouxii, Mucor ory:ae. Oidium lactis. F.ndomyces magnusii. 



