Notes on scientific research. 121 



leaves of Mentha aquatica. The fusarium stalk rot, caused by the mycelium of Fusarium 

 Dianthi. Prid et Del. and F. roseum. Meng. (Tuberculariacece) , which occurs occasionally 

 in mint plantations is not quite as harmless as the preceding fungi. In this disease, 

 the stalks turn blackish-brown at the base and wither. The following measures are 

 recommended against this disease: —Destroying of all infected plants, suspending the 

 cultivation of mints for several years, and, if necessary, disinfecting the soil. 



Phytophysiological Notes. 



With the object of studying the process of formation, in the plant, of the essential 

 oil. J. Politis 1 ) investigated the secretory hairs of various labiatse and' geraniaceae. In 

 the secretory cells of the hairs, during the first stage of their formation, numerous 

 oblong and twisted "chondriocontes" 2 ) are observable which contain a tannin com- 

 pound. These "chondriocontes" widen gradually at each of their ends and separate 

 thus that both from each a separate globule. These globules increase in size and pass 

 over into the vacuoles of the cell where in course of time they are dissolved by the 

 vacuole liquid. The content of the vacuole then shows feeble refractory power, and 

 instead of the disappearing tannin, essential oil is formed 3 ). 



E. Canals 4 ) investigated the influence exercised by rays of varying icave-lengths 

 on the formation of essential oil in the plant. For this reason, the author transplanted 

 young thyme plants grown in uncultivated land into pots and arranged them in boxes 

 beneath ordinary (1), blue (2), or red (3) glass panes. After lapse of 20 days, all the 

 plants in box (1) were in bloom, but showed pale blossoms, long stalks, and light green 

 leaves. The plants in box (2) were like the former, some of them had faded away. In 

 box (3), but a very few plants had attained a poorly blossoming stage, their stalks were- 

 excessive long and the leaves very broad. The thyme plants had entirely lost their 

 xerophilous character. The oils distilled from the various plants showed the following 

 percentage of thymol: — 



Plants in box 3 (red glass) . . . 25.5 per cent, thymol 



„ „ 2 (blue glass) ... 36 „ 



„ „ 1 (ordinary glass) . 45 



„ from open air 52 „ „ „ 



From these observations the author concludes that the thymol content of the oil 

 decreases to the same extent as the plant loses its xerophilous character, and that the 

 chemically active blue rays exercise an unfavourable influence on the formation of. 

 thymol which is far more marked with the calorific red rays. 



The result of this study is in accord with earlier investigations and might have 

 been expected. According to Lubimenko and Novikoff 5 ), light is indispensable in the 

 formation of essential oil in the plant, but increased etiolation, at least within certain 

 limits, raises the yield of oil. - On the other hand 6 ), in most cases the rays of high 



1 ) Compt. rend. 173 (1921), 98. — 2 ) The term "chondriocontes" is a newly-created one and is not to 

 be found in the literature at our disposal. With "chondres" various species of granules are designed which 

 occur in the nucleus and form the connections between the lince in the frame. — 8 ) Already years ago, various 

 scientists, e.g. Heckel and Schlagdenhauffen {Compt. rend. 114 [1892], 1291) favoured the theory that there exists 

 some connection between the formation of essential oil in the plant and the tannins. — 4 ) Bull. Roure Bertrand 

 Fils, April 1921, 8. — 8 ) Bull, applied Bot. 1 (1914), 697. As per Bot. Zentralbl. 128 (1915), 696. The abstract 

 on basil oil published in The Amer. Perfumer 10 (1915), 265, without mentioning the source, pertains to this 

 paper by Lubimenko and Novikoff which we dealt with in our Report 1916, 5. — 6 ) Pfeffer, Pfl-anzeu- 

 physiologie, 2 nd ed. vol. II, p. 117! 



