84 pringsheim's researches on chlorophyll. 



fifteen minutes at 50° C; in Spirogxjra, Ulothrichecs, Coleo- 

 chatecE, (Edogoniece, and their allies, a temperature of 45° — 

 60° destroys the reaction. For plants with isolated chloro- 

 phyll-corpuscles, such as Chara and Nitella, and soft-leaved 

 plants as Elodea, Callitriche, Sec, a quarter to half-an-hour 

 in water of 50° is enough. Fo7itinalis also takes fifteen 

 minutes at 50° C. In Mnium, fern emhryos, Selaginella, and 

 in Vallis7ieria, a longer time at 50° C. is required, or the 

 temperature must be raised to 60° — 80° C. Boiling or 

 steaming brings it about more rapidly. Fifteen minutes 

 steaming is enough, as a rule, though at times half-an-hour 

 or an hour is wanted. It would appear, that in all these 

 cases the hypochlorin is destroyed by heat, and vanishes 

 without damage to the colouring matter or destruction of 

 the chlorophyll-corpuscle or mass itself. 



Other hurtful influences, which only to a slight extent 

 change the normal character of the cell-content, destroy the 

 hypochlorin without there being any visible change in the 

 chlorophyll-corpuscle itself. Cells in such an abnormal or 

 unhealthy state occur frequently in cultivated specimens of 

 Sjnrogyra or of Nitella. They can easily be produced artifi- 

 cially if the conditions of life are made unfavourable. If a 

 cell of Spirogyra be injured mechanically, or if the condi- 

 tions for its existence are not suitable, the first sign of 

 unhealthiness is seen in the chlorophyll-bands, which lose 

 their outline, contract, and if the conditions be continued 

 disintegrate to formless particles. Such signs are very 

 frequently indication of a faulty nutrition only. The colour 

 of the bands is not in the least affected, and the amylum- 

 bodies and oil-drops remain undestroyed. Many cells in a 

 filament may be quite healthy, and others may show all 

 stages of commencing sickness. On treating with hydro- 

 chloric acid, the healthy cells alone show hypochlorin, 

 none is found in the unhealthy cells, or only a slight trace 

 when the diseased state is not very pronounced. It is pos- 

 sible that some of the cases already referred to where one 

 or more cells in the midst of a tissue rich in hypochlorin 

 show no trace of this substance, and in which the hypo- 

 chlorin was supposed to have been completely used up in 

 the nutritive process, are instances of disease. The cells, 

 though not visibly so, may be really in an abnormal con- 

 dition, which has resulted in and is made known by the loss 

 of their hypochlorin. 



Associated, then, with the colouring matter, hypochlorin is 

 a substance universally present under normal conditions in 

 chlorophyll-corpuscles, whatever their shape. These having 



