PHYSIOLOGY. 



the inheritance of two nomenclatures of parts 

 of the cell, this lack of consonance in views con- 

 cerning the structure of cell protoplasm is trace- 

 able in the main to the fact that they are largely 

 based on details visible both in fresh and fixed 

 cells which are the result of the physical changes 

 that the living substance undergoes -in the act 

 of dying or under the influence of fixatives. A 

 study of the action of reagents upon colloidal 

 matter shows, according to this author, that 

 when an insoluble modification is formed there 

 is a separation of solid particles which are largely 

 molecular aggregates, and that these become 

 linked together to form a comparatively coarse 

 solid framework having the form of an open net 

 which holds fluid in its meshes. In some cases, 

 however, the reagent is partially miscible with 

 the colloidal mixture, when the latter is modified 

 in degree, but remains the same in kind. The 

 structure of dead matter which \vas once living 

 may also be referred to the clotting phenomena 

 of death as well as to post-mortem change. 



In presenting the physiological aspects of sym- 

 biosis at the British Association, Prof. Marshall 

 Ward distinguished between parasitism, where 

 an organism grows upon another for its own 

 benefit, and symbiosis, where two or more organ- 

 isms are mutually dependent upon one another. 

 A characteristic instance of symbiosis is that of 

 lichens, which are dual organisms of alga and 

 fungus. Other instances are afforded by the algse 

 in the stems of Gunnera and the roots of Cycas, 

 in the fronds or thallus of Anthoccros and other 

 plants. The roots of many humus plants are 

 curiously swollen and modified by the presence of 

 fungi, which do not injure the plant but link its 

 roots to the decomposing leaves around. Bud- 

 ding and grafting are operations involving a pro- 

 cess of symbiosis. The nodules on the roots of 

 leguminous plants are agents through which they 

 obtain nitrogenous food. Other cases are those of 

 fermentations, which are all mixed, the decom- 

 position of cellulose, and the direct alcoholic fer- 

 mentation of starch by the simultaneous action of 

 two fungi. Symbiosis in animals is exemplified by 

 green infusoria, the hydra, sponges, etc. The gen- 

 eral effect of the symbiosis of two or more organ- 

 isms is observed to be that each in some way pro- 

 motes and stimulates the growth and vigor of the 

 other. But when we come to inquire as to the 

 processes which increase the functional activity of 

 one organism by another living symbiotically 

 witli it, the matter presents many difficulties. In 

 some cases of close symbiosis, researches have 

 made it practically certain that the provision of 

 definite food materials by the one symbiont for 

 the other may be an important factor. In other 

 cases the advantage derived is one of protection 

 from some injurious agent. " But there is evi- 

 dence which suggests that mere nutrition or pro- 

 tection is not the only, or even the principal, fac- 

 tor involved. It is well known that the products 

 of fermentative actions are frequently poisons, 

 and we all know of cases where such poisonous 

 excreta of living cells act as stimuli to other cells 

 if supplied to them in minimal dpses and very 

 gradually." Several observers have shown that 

 in presence of a particular food substance the 

 living cell is stimulated to produce and excrete 

 a particular enzyme, while the substitution of an- 

 other food may cause the excretion of a dif- 

 ferent organism. There is evidence in support of 

 the hypothesis that one symbiont may stimu- 

 late another by excreting some body which acts 

 as an exciting' drug to the other, "it is known 

 that the accumulation of the products of metabo- 

 lism by a cell tends to inhibit its activity, and 



that if the metabolite can be destroyed or re- 

 moved as it is formed the cell concerned can go 

 on working; and similarly with the accumula- 

 tion of the products of ferments and enzymes 

 Now if we have two organisms, one accumulat- 

 ing the product and the other removing it the 

 process will go on continually with undimini'shed 

 activity. 



A discussion of the chief features in plant phys- 

 iology in which notable progress has been made 

 during the past decade constituted the subject of 

 the chairman's address of Prof. Charles K. Barnes 

 before the botanical section of the American Asso- 

 ciation at the Columbus, Ohio, meeting. The au- 

 thor showed that the great advances in plant 

 chemics and physics, the progress in the investi- 

 gation of causes of plant form, the widening ideas 

 of the property of irritability, the investigation 

 of the social relations of plants, and the minute 

 study of cell action despite their diversity point 

 to one end and purpose. This is the solution of 

 the fundamental problem of plant as well as of 

 animal physiology, of the constitution of living 

 matter. The secret lies hid, intrenched within 

 the apparently impregnable fortress of molecular 

 structure. The attacks upon it from the direction 

 of physical chemistry and physiological mor- 

 phology, of irritability, of ecology, and of cytol- 

 ogy are the concentrating attacks of various di- 

 visions of an army upon a citadel some of whose 

 outer defenses have already been captured. The 

 innumerable observations are devised along par- 

 allel lines of approach, and each division of the 

 army is creeping closer and closer to the inner 

 defenses, which yet resist all attacks and hide the 

 long-sought truth. One outer circle of defenses , 

 yet remains untaken, and until that falls it would 

 seem there is little hope of capturing the inner 

 citadel. More must be known of the constitution 

 of dead substances chemically related to the liv- 

 ing ones. When the students of chemistry can 

 put the physiologists in possession of the facts 

 regarding dead proteids the attacks will be re- 

 newed more directly with greater vigor and great- 

 er hope of success. It is not possible to prove 

 to-day that life and death are only a difference 

 in the chemical and physical behavior of certain 

 compounds. 



Respiration. Experiments by J. Lorrain 

 Smith on the pathological effects due to increase of 

 oxygen tension in the air breathed are regarded by 

 him as supplementary to the investigation on the 

 normal process of respiration of oxygen which 

 was previously made by Dr. Haldane and him- 

 self. In that investigation it was shown that the 

 absorption of oxygen by the lungs is an active 

 physiological process. The experiments now de- 

 scribed by Dr. Smith show that at a tension a 

 good deal higher than that of ordinary air oxy- 

 gen has the effect on the lungs of an irritant, 

 and produces inflammation. The experiments 

 also show that the toxic effects described by Bert 

 occur at a tension which is much higher than 

 that required to produce the inflammatory effect 

 on the lungs. Further, it is shown that when the 

 lungs are damaged the tension required for the 

 production of this toxic effect is in a marked de- 

 gree higher than that required when the lungs 

 are normal. The experiments have a direct bear- 

 ing on the pathology of caisson disease, a subject 

 which the author does not discuss fully at pres- 

 ent; but he considers that the oxygen tension of 

 the high-pressure atmosphere is probably to be 

 regarded as taking part along with the rapid 

 decomposition predicated by Bert in his investi- 

 gation of the subject in the production of that 

 disease. Apart from this, the experiments have 



