MYSTERY OF THE CELL 37U 



vantages; the resistance to injurious influences; the avoidance or 

 encompassing of insuperable obstacles ; the punctuality with which 

 aU the functions are performed ; the periodicity which occurs with 

 the greatest regularity under constant conditions of environment ; 

 nor, above all, the fact that the power of discharging all the op- 

 erations requisite for growth, nutrition, renovation, and multipli- 

 cation is liable to be lost. We call the loss of this power the death 

 of the protoplasm" (vol. i. p. 51). 



Growth hy Cell-Division: What it Implies 



As the account now given of the most recent discoveries as 

 to what actually takes place in the living cell preparatory to 

 its division and subdivision, wliich are *\ 3 very first steps in 

 the growth or building up of the highly complex 'and perfect 

 animal or plant, is very technical, and will be perhaps unin- 

 telligible to some of my readers, I will now give a very short 

 statement of the process with a few illustrations, and remarks 

 as to w^hat it all really means, and how" alone, in my opinion, 

 it can possibly be explained. 



The egg is a single cell with a special central point or organ, 

 called the nucleus, and it is this nucleus which makes the cell 

 a germ-cell. That this is so has been proved in many ways, — 

 in plants by grafting or hudding, where the ilower-bud which 

 contains a germ-cell, when inserted in the bark of a differ- 

 ent variety, and sometimes a different species of plant, repro- 

 duces the exact kind of flower or fruit that characterised the 

 tree or bush the bud was taken from, not that of the plant of 

 which it now^ forms a part, and whose sap forms its nourish- 

 ment. 



Again, Professor Boveri deprived an Qgg of a species of 

 sea-urchin {Echinus microtuherculatus) of its nucleus, and 

 then fertilised the egg with the spermatozoa of anotlier species 

 {Sphcerechiiiu^ qranidaris). The egg so treated developed 

 larva? with the true characters of the latter species only, so 

 that the main substance of the egg provided nutriment for 

 the offspring, but did not transmit to it any of it^ parental 



