824 SUMMARY OF CURRENT RESEARCHES RELATING TO 



common to both the organic kingdoms, when it is considered that it 

 is the chemical equivalent of the waste products which are the result 

 of the contractility which is common to all cells, whether vegetable 

 or animal : " the plasmodial stage which terminates the cycle seems 

 an almost mechanical union of exhausted cells." This position is 

 further supported by an experiment which tends to show the con- 

 vertibility of one morphological stage into another, by mere physico- 

 chemical agencies, viz. the conversion to an undifferentiated condition 

 of an ActinosphcBrium treated with dilute ammonium carbonate. The 

 origin of plants and animals respectively, from the alleged Protistan 

 substratum of form-cycles is thus explained : — " If division takes place 

 continuously in the encysted stage, the resultant multicellular aggregate 

 is a vegetable ; if in the amoeboid or the ciliated a more or less distinctly 

 animal organism arises. In plants the cell-cycle is represented almost 

 solely by the resting-stage, though the ciliated phase lingers on here 

 and there in the antberozooid, and the amceboid in the oospore." As 

 undisguised examples of the cell-cycle, he cites Magosphcera and the 

 gastrula of sponges, but be considers that the tissue-development of 

 all the higher animals should be interpreted in the same manner. 

 He finds the theory to have a bearing on the physiology even of the 

 most compound and individualized animals, inasmuch as the functions 

 of the body are the result of the aggregate functions of its cells, and 

 are explained by variations or phases of the activities of them ; 

 pathological phenomena are referred to the same source. 



Of the various modifications and variations which cells present, 

 and of the physiological phenomena exhibited by cells as units, 

 Mr. Geddes attempts an explanation, based on the observations of 

 Darwin, on the aggregation of protoplasm in the cells of insectivorous 

 plants under certain conditions. For example : " On this view the 

 granules of an amceba or torula are (disregarding, of course, sap- 

 vacuoles and fat-globules) aggregation-products, the clear ectoplasm 

 when present being merely a portion of the homogeneous protoplasm 

 in which aggregation is not occurring. The more or less granular 

 character of the Amoeba would thus depend on the state of nutrition 

 and the quality and quantity of external stimuli, and would naturally 

 be least evident in the resting-state." This he applies to the cells of 

 higher animals, and reconciles it with that view of their granules 

 which regards them as intersections of a network of filaments by the 

 fact of Darwin finding linear aggregation- masses as commonly as 

 spherical ones. The radiate arrangement of granules accompanying 

 the development of ova and the strige of the " Kern-spindel " are both 

 treated as dependent on aggregation. The motions of the Amoeba are 

 dependent on the same circumstance ; and from this the contraction of 

 muscle can be understood in connection with its minute structure and 

 the variations which this exhibits in different states of contraction, the 

 different sets of granules and globules being aggregation-elements 

 the sum of whose tendencies to aggregation, exerted most fully during 

 contraction, when they are massed together and render the fibril homo- 

 geneous, being expressed by the shortening and broadening of the 

 muscle and the overcoming of resistance. 



