Conditions of its Production in the Plant. 323 



respect to the oil separated, hydrochloric acid calls forth no 

 further change in the behaviour of the chlorophyll-bodies ; 

 and the great difference herein shown in the action of hydro- 

 chloric acid upon chlorophyll-bodies, according as the latter 

 have or have not previously been heated, appears the more 

 noteworthy, as the chlorophyll-colouring-matter in itself un- 

 dergoes no essential alteration by heating, especially when 

 the application of heat is of short duration and the tempera- 

 tures are not high. For the modification that chlorophyll 

 undergoes spectroscopically when heated in water appears to 

 be chemically of no great consequence ; so that, as is well 

 known, for many reasons it might even be advisable, in 

 order to render the solution of chlorophyll more persistent, 

 to boil the green tissues with water before the extraction. 



The fact remains established : — The remarkable reaction 

 that hydrochloric acid produces in unhealed chlorophyll-bodies 

 does not occur in those which have been heated ; and the cause 

 of its non-occurrence cannot be sought in any alteration of 

 the colouring-matter. 



As the interruption of the hydrochloric-acid reaction for 

 hypochlorin by previous heating of the tissues is fitted to give 

 us a closer insight into the properties of that body, it may 

 be here specially elucidated by a few examples. 



If filaments of Cladophora in the fresh state are treated 

 directly with hydrochloric acid, the larger hypochlorin-masses 

 (already repeatedly described) make their appearance in every 

 cell without exception. In strongly vegetating filaments with 

 abundant cell-contents, the latter are, as it were, overcrowded 

 with the masses formed by the hypochlorin-mixture. But if 

 the filaments of Cladophora are previously heated only from 

 five minutes to a quarter of an hour in water of 50° C. 

 ( = 122° F.), under which treatment the cell-contents remain 

 essentially unaltered in colour and form, and even appear 

 more transparent than before, and starch-grains and amylum- 

 foci do not swell up, nothing of the hypochlorin-mixture is to 

 be detected in them after the same treatment with hydrochloric 

 acid. All those numerous larger drops, scales, &c. which the 

 hydrochloric acid brings forth in the fresh are wanting in the 

 heated filaments. 



A similar behaviour is presented by filaments of CEdogo- 

 ninni) Mesocarpus, and Spirogi/ra, and, in general, in Alga3 

 with so-called amorphous chlorophyll. In these a still 

 shorter exposure to heat and a lower temperature will often 

 suffice. 



Even in the well-limited chlorophyll-bodies of the Nitellw 

 and Charo3, and many higher plants with delicate leaves, e. g. 



