1891.] MICROSCOriCAL JOURNAL. 127 



itself a sufficient endowment to enable protoplasm to be " tlie physical 

 basis of life " which it has very properly been called. For, armecl with 

 this power alone, it could only at best be little better than at the mercy 

 of hazard as regard its supplies of substance, and one of the most no- 

 ticeable facts of living things, their wonderful increase and spread, would 

 not be easily interpreted. Protoplasm has, then, a second power — that of 

 altering the relative position of the molecules of its substance, whereby 

 a change of its shape as a mass is brought to pass. By this power 

 masses of protoplasm can change position and come into new relations — 

 a most important endowment for all living things, since it not only may 

 bring them into new and unexhausted supplies of substance necessary 

 for the exercise of metabolism, but may also give them numerous possi- 

 bilities of duect interaction upon each other which may be of great im- 

 portance. The masses can also change their shape and change the 

 position of connected parts. By virtue of this power muscle can pull 

 on tendon and this on bone, and through motion in protoplasm joints be 

 bent. As before remarked, this power is brought into great prominence 

 in the animal body while the metabolic power is inconspicuous though 

 universally present, energy being furnished for movement by katabolism, 

 and this form of metabolism being the chief one exercised by animal 

 protoplasm. 



7. Irritability. — The third power of protoplasm, its irritability, may 

 be conceived of as an oscillation among the molecules of the structure 

 caused by a disturbance from outside the protoplasm, which oscillation 

 is transmitted to all parts of the protoplasm and in a wholly mysterious 

 wav leaves a trace of its effect, whereby every subsequent similar dis- 

 turbance more easily causes a repetition of the oscillation. This last 

 power of protoplasm is at the foundation of the nervous system in animals. 

 It is present in the plants, but in the higher ones is not obvious, though 

 doubtless exercised. The irritation of protoplasm, or in scientific lan- 

 guage stimulation, may imitate the action of any of its other functions, 

 as motion or metabolism, and, in a complex body, this power makes 

 the co-working of parts possible. Some of the most materialistic of 

 philosophers think that when these powers of protoplasm are fully un- 

 derstood they will be found to explain all the phenomena of life, but 

 we must most carefully notice that in all' of this analysis we do not in 

 the least open or decide the underlying philosophical question of the 

 source and guiding control of these forces and the myriads of results of 

 their varied combinations. Science goes no fiirther than to recognize 

 these primary facts : first, that protoplasm isa definite material substance, 

 a mixture of saline water and very complex and unstable chemical 

 compounds ; second, that living protoplasm can perform acts which we 

 class as metabolism, motion, and sensation. The explanation of these 

 data is metaphysical and the province of philosophy. 



Our next task will be to examine some of the forms under which 

 protoplasm exists in living bodies, and the way in which these powers 

 are exercised in the cells and tissues. 



\ To be coniintted.~\ 



Pure Culture of Gonococcus. — Von vSchr(>tter and Winkler recom- 

 mend the albumen of plover's eggs as an excellent nutritive medium 

 for easily obtaining pure cultivations of Neisser's gonococcus. 



