CHAP, in LIVING MATTER 65 



simple or complex organism, indeed, exhibits a certain capacity of 

 adapting itself to an environment and nutrition different from 

 those to which it has been accustomed, provided only that the 

 change is effected very slowly and gradually. In consequence of 

 this adaptation, temporary modifications of the specific characters 

 ensue. According, however, to certain experiments of Nageli, 

 these are not persistent, but quickly disappear when the organism 

 is brought back to its original environment and alimentation. 



In order to form an adequate concept of the adaptability of 

 various organisms to unusual conditions in respect of nutrition, 

 we may refer to certain bacteria, recently investigated by 

 Winogradsky, which he calls sulphur or iron bacteria. The 

 sulphur bacteria are represented by a family of microbes, which 

 can only live in the water of bogs or marshes, where, owing to the 

 decomposition of vegetable and animal matters, there is a great 

 development of hydrogen sulphide. This they absorb, oxidising it, 

 and setting free the sulphur, which they accumulate in the body 

 of their cells in the form of highly refractive granules. On 

 subsequent oxidation, these granules give rise to a formation of 

 sulphuric acid, which is excreted as such. The iron bacteria live 

 in marshy water, where ferrous carbonate is found in solution ; 

 this they take up, and convert it into ferric carbonate, which readily 

 decomposes on excretion, and the precipitate of iron oxide forms 

 the ochre -like deposit known as meadow-ore. 



Both sulphur and iron bacteria perish when brought into 

 spring water, which contains no hydrogen sulphide or ferrous 

 carbonate, while these compounds act as poisons to all other living- 

 beings. They must, therefore, have undergone a permanent adapta- 

 tion to a quite exceptional form of environment and nutrition. 



Whatever the nature of the food-stuffs appropriate to the 

 various organisms, they are indispensable to the maintenance of 

 life. Absolute or relative deprivation 

 of food produces a state of inanition, 

 during which the organism primarily 

 consumes the reserve materials stored 

 up in the body of the cell, and then 

 absorbs its own protoplasm, shrinking 

 more and more, until it finally perishes 

 when the protoplasm has no longer 

 enough potential energy to maintain the 

 balance of metabolism (Fig. 17). v^- IT. - 



, . , . . , , ,. . , ,. ciliated infusorium. (Jensen.) a, 



The individual living elements ot under normal COI1( iitions ; &, in 

 which the tissues and organs of the S^*Sj l ?a tt d J 

 higher animals are composed draw all pnved of granules. Magnification, 



. , a j -liO diameters. 



their nourishment from a common fluid, 



the lymph, which circulates in the interstices of the tissues. 



During inanition, the total consumption of the organism is not 

 VOL. i F 



