NA TURE 



[July 5, 1900 



The linked up chains and networks of protoplasm- 

 molecules— which do not correspond to the networks of 

 coagula of other hypotheses— are termed stereoplasm^ 

 the bath of liquid containing proteids, carbohydrates, 

 fats, minerals, molecular oxygen, etc. — i.e. in which are 

 dissolved all the food-materials as well as all the products 

 of shattered molecules — is termed hygroplastn. The 

 osmotic attraction for water of the newly formed mole- 

 cules (imbibition) would set up pressures resulting in 

 such ruptures of the linked up series. 



Kassowitz supposes that every molecule of the stereo- 

 plasm is liable to disruption when stimulated by any 

 mechanical shock, chemical reaction, thermal or electri- 

 cal radiation, &c., and that the immediate results of the 

 shattering of a given molecule are somewhat as follows. 

 The products of disruption are partly atom-groups which 

 at the moment of disruption display unsaturated affini- 

 ties of so energetic a character that they split the mole- 

 cules of atmospheric oxygen brought into the hygro- 

 plasm and combine to form saturated compounds such 

 as CO2 and OHg ; partly atom-groups containing nitro- 

 gen, which rearrange themselves into bodies such as pro- 

 teids, and can be utilised again in building up new 

 protoplasm-molecules, or temporarily stored, or excreted 

 bodies of various kinds. 



The combustions involved in the formation of CO2 

 and OH2, and constituting respiration, of course result 

 in the evolution of heat : they are, in fact, explosions, 

 and each such explosion acts as a new stimulus and 

 shatters more protoplasm-molecules, with results and 

 consequences as before, and it is this repeated play 

 which constitutes the propagation of a stimulus — either 

 irregularly in all directions or, if the stereoplasm is 

 linked up more especially along certain tracts (nerves), in 

 definite directions. The accumulation of metabolic 

 products may result in blocking the mesh works, and so 

 impeding the access of oxygen, and the activities slow 

 down accordmgly. In the pauses of rest between such 

 destruction changes, the building up of new protoplasm- 

 molecules is accomplished, and this act of restitutive 

 construction is assimilaiioti, while the interposition of tHfe 

 new molecules between those already in existence is 

 growth. 



In illustration of the kind of forces at work in the 

 construction of a new protoplasm-molecule by assimila- 

 tion, Kassowitz points to such phenomena as selective 

 crystallisation, whereby a minute crystal of Glauber's 

 salt, for instance, in a mixture of the same substance 

 and saltpetre induces the crystallisation of the former 

 only ; and to such cases as mixtures of two optically 

 active salts in which the crystallisation of one only is 

 determined by introducing a minute crystal of like 

 optical activity, and to other cases where sub- 

 stitutions of one atomic group by another can be 

 brought about. These illustrations are not intended to 

 serve as examples of what happens, but to show that 

 the forces concerned in chemical attractions may well be 

 those at the bottom of the phenomena of assimilation of 

 like to like in the stereoplasm, or of the building up into 

 the complex molecule of protoplasm of atom-groupings 

 of similar or not very dissimilar nature ; and although we 

 have no hope of following the various stages in detail, it 

 is argued that stereochemistry has at least taught that 

 NO. 1 601, VOL. 62] 



forms and configurations may result from such molecular 

 phenomena as those indicated. 



The arguments to show that the unstable protoplasm- 

 molecule, the lability of which is increased by radiant 

 energy absorbed from without, is itself devoid of oxygen, 

 is capable of reducing highly oxidised food-substances, 

 of absorbing water and setting up osmotic phenomena, of 

 giving rise to metabolites of various kinds, &c., &c., are 

 too long to reproduce here, and I must content myself 

 with one illustration only, of the many given in the re- 

 mainder of the first volume, to show the application of 

 the hypothesis to special cases. 



When the pseudopodium of an Amoebi has reached a 

 certain development it suddenly retracts, or rather 

 collapses, for Kassowitz regards the phenomenon as a 

 rapid tumbling to pieces of the molecular structure, 

 owing to stimulation : certain protoplasm-molecules are 

 shattered, atom-groupings of carbon and hydrogen split 

 the molecular oxygen and are at once burnt to CO^ and 

 OH2, the heat-vibrations evolved during the combustion 

 shattering mdre molecules, and so on, throughout that 

 part of the mass. This process exhausted, a period of 

 restitution sets in, and new molecules are built up from 

 the fragments of proteids, carbohydrates, fats and 

 mmeral substances at disposal, and become interpolated 

 between those which had escaped destruction, and a new 

 pseudopodium is put out by assimilative growth. Among 

 other arguments for the view that this is really a process 

 of growth, Kassowitz points out that the rate of protrusion 

 of such a pseudopodium, rapid as it appears under a 

 high power, is really not much more rapid than the 

 growth of a stem of asparagus, a mushroom or a 

 bamboo. 



The most interesting part of the second volume will, 

 for most readers, be those dealing with the questions of 

 variation and evolution. 



Having elaborated his theory of the essential structure 

 and mode of working of protoplasm, Kassowitz proceeds 

 to consider the complexities which arise, first, on the 

 differentiation of the nucleus and " germ-plasm," and 

 then on the further divisions of labour involved in multi- 

 cellular organisation. In these cases the nucleus, internal 

 cells, &c., obtain for their immediate environment, not the 

 outer world, but protoplasm exposed to the action of the 

 latter and modified by it. Whereas undififerentiated proto- 

 plasm obtains its supplies of food and energy direct from 

 the environment, the nucleoplasm can never do this, as it 

 never comes in contact with it. Its protoplasm-molecules 

 must select their assimilable materials from the fragments 

 of shattered cytoplasm molecules, and if any modifications 

 in the modes of disruption and reconstruction of the 

 molecules of the stereoplasm — i.e. in the " somatoplasm " 

 of authors — have been brought about by the actioti of the 

 environment, the slightly altered atomic groupings and 

 modes of disruption thus put at the disposal of the nucleo- 

 plasm — i.e. the "germ-plasm" of authors — will affect the 

 building up and modes of disruption of the new mole- 

 cules of this, and these in their turn react again, and 

 so on. 



This short summary of a long argument must serve 

 to indicate the nature of the author's grounds for con- 

 cluding that Weissmann's contention against the trans- 

 mission of acquired characters cannot be upheld. It ifv 



