NO. T. | REGENERATIVE ENERGY. 43 
(p. 84) takes no share whatever in the production of spores ; 
and thus it appears that the central capsule is the seat of the 
reproductive as well as the regenerative energy. During ‘‘ vege- 
tative life” the various functions (digestion, locomotion, sensa- 
tion, etc.) all appear to be performed by the extra-capsular 
cytoplasm ; but the whole functional activity, as supposed by 
Brandt, is under the vegz/ative influence of the central capsule. 
In the Sphzerozoa colonies the division of labor is carried still 
farther ; for while the pseudopodial rays have their special func- 
tions, certain definite areas of the matrix (“ Klumpen von As- 
similationsplasma’’) provide for the digestion of the starch 
granules which are produced by symbiotic algae; and different 
layers or zones are distinguishable even in the central capsule. 
That there should be such a complete separation of functions 
between the central core and the cortical layer of the same body 
of cytoplasm is no less instructive than it is remarkable. It isa 
capital illustration of the possibilities of organization and the 
physiological division of labor without any corresponding divis- 
ion into distinct morphological units. 
Recent studies tend to show that the only important sub- 
stance conveyed into the egg by the spermatozoon is that which 
takes the form of the male pronucleus. The unavoidable con- 
clusion would appear to be that the pronuclei are the sole 
bearers of hereditary tendencies. This is unquestionably a 
point of cardinal importance, and it furnishes the strongest 
argument that has yet been advanced in favor of regarding the 
nucleus as the seat of the formative power. This side of the 
question could not be fairly dealt with within the limits of 
the present paper, as it would lead to a consideration of the 
whole problem of heredity. It is my purpose, however, to re- 
turn to this subject at no very distant date. 
The Idea of a Formative Power.— Let us now consider 
whether any rational basis can be found for the idea of a 
formative power as a resultant from, and an expression of, 
physiological unity. I am fully conscious that the subject is 
one of profound mystery, the solution of which appears to 
lie as far beyond our grasp to-day as at any time in the 
past. We draw nearer to the problem, but the effect is rather 
to enhance than to reduce its apparent magnitude. Every step 
in advance only brings us to a keener sense of the subtle and 
