January, 1913. 



KNOWLEDGE. 



13 



the formation of the amido-acids themselves is a 

 complex process. In the plant-cell in some cases, as 

 was shewn by Pfeffer, it appears that calcium nitrate 

 is decomposed by oxalic acid, nitric acid being set 

 free and utilised in the formation of more complex 

 nitrogenous compounds, and it seems that at times 

 hydrocyanic acid may be used in the same manner. 



Living protoplasm is constantly undergoing a 

 series of oxidative and reconstructive reactions, and 

 it is quite impossible to make a sharp line of distinc- 

 tion between the so-called anabolic and katabolic 

 processes going on in the living substance ; these 

 two types of reaction are always going on hand in 

 hand, and we must look upon the protoplasm as 

 being the seat of a large number of oxidative and 

 constructive processes, some of which are always 

 going on ; others, such as those concerned with the 

 storage of food-substances (proteid, carbohydrate or 

 fat), taking place only at certain periods, depending 

 to a large extent upon the needs of the organism at 

 the time. 



It will be seen, then, that normal metabolism is a 

 highly complicated series of interactions between 

 various compounds in the cell; when the nutrition 

 of a cell is modified in any way, either in quantity, 

 quality, or both, the protoplasm is certain to react in 

 some special manner to the changed conditions. 

 Nutrition may be so profoundly modified that the 

 cell may not be able to earn- on any kind of 

 metabolism, whether proteid, fat or carbohydrate, 

 and in such a case function will be stopped or at 

 least suspended. In many instances, when the 

 medium surrounding a cell contains substances which 

 act adversely upon metabolism (toxins, alkaloidal 

 poisons, and so on), the protoplasm will not react in 

 a manner adequate to cope with surrounding 

 conditions, and subsequently the noxious substances 

 gain the upper hand, the living substance passing 

 into a condition known as "fatty degeneration"; 

 this must be distinguished from true "fat metabolism" 

 in the cell, since in the degenerative process no 

 reconstruction takes place as in the normal cell. 



Less virulent irritants acting upon the cell over 

 long periods of time (chronic irritation) may, in the 

 long run, produce marked changes in metabolism, 

 and cells in which such perversion of normal 

 metabolic processes has taken place may, if carried 

 from one part of an organism to a remote part, set 

 up similar perversions in the cells amongst which 

 they settle. It seems, in fact, that once the cycle of 

 metabolic changes in a cell has undergone a complete 

 alteration, a cell is able to influence others in its 

 immediate vicinity ; it is possible that a substance or 

 substances of the nature of toxins (cytotoxins) or 

 enzymes may be produced which have a profound 

 effect upon normal metabolism. 



As evidence of the power which small quantities 

 of certain substances have when distributed through- 

 out a cell-aggregate, the various internal secretions 

 manufactured in the animal body may be taken ; 

 there is no doubt nowadays that the thyroid gland, 

 the suprarenal capsules, the islets of Langerhans in 

 the pancreas, and the ovary manufacture internal 

 secretions which are of immense value to the cells of 

 the bod)- in aiding the furtherance of normal 

 metabolism, since, when any of these internal 

 secretions is absent or produced in excess, it is found 

 that metabolism is profoundly altered. The internal 

 secretions formed in these bodies are in most cases 

 protein substances, some of which are possiblv akin 

 to enzymes in their action ; but their constitution is 

 in many cases obscure, although their physiological 

 action is definite enough in a few instances. 



The above brief considerations will enable the 

 reader to grasp the fact that the cell possesses a 

 highly complex organisation, and that the processes 

 going on in the protoplasm are of such a nature as 

 to call upon our keenest powers of observation and 

 experiment for the purpose of their elucidation : and 

 it will have been gathered that not one of the least 

 remarkable features in connection with cytological 

 phenomena is the infinite capacity of the living cell 

 to react to stimuli of varying nature, and to adapt 

 its metabolism to altered external conditions. 



GLOW WORMS AND LIGHTNING. 



By ROBERT W. PETHEN. 



The common glow worm (Lampyris noctiluca) is a 

 most interesting member of that large order of 

 insects, the Coleoptera, and before proceeding to 

 describe how I found this insect to be susceptible to 

 the influence of lightning, I would like to make a 

 few observations on its light-giving capabilities as 

 shewn by the perfect female and also by the same 

 insect when in the larval stage. 



It may not be out of place to mention here that 



the glow worm gives forth a greater or lesser amount 

 of light in every stage of its existence, including the 

 egg, which "glows" more or less brightly when 

 moistened with water and held in a dark place. 



The beautiful phosphorescent light displayed by 

 this little beetle is far more familiar than the insect 

 itself, and although the female is popularly credited 

 with being the cause of the twinkling lights to be 

 seen amongst the grass and hedge-banks in certain 



