August 23, 1895.] 



SCIENCE. 



213 



After this fusion of the father and mother 

 germ cells, the single cell thus formed, like 

 the amceba, divides into two, and these into 

 four and so on, but unlike the amoeba all 

 the cells remain together. Within this 

 cellular mass, as if by an unseen builder, 

 the cells are deftly arranged in their place, 

 some to form brain, some heart, some the 

 digestive tract, others for movement, so 

 that finally from the simple mass of cells, 

 originally so alike, arises the complex or- 

 ganism, fish or bird, beast or man. How 

 perfectly the word offspring describes the 

 life process in the production of this new 

 being ! That the child should resemble 

 both father and mother is thus made intel- 

 ligible, for it is a part of both. Yes, fur- 

 ther, it may resemble grandfather or great 

 grandfather or mother, for truly it is a part 

 of them, their life conserved and continued. 

 There is no new life, it is only a continua- 

 tion of the old: ' Omne vivum ex vivo,'' all life 

 from life. But the demonstration of this 

 prime fact required a microscope, and it 

 is an achievement of the last half of this 

 century. How counter this statement still 

 is to the common belief of mankind we 

 may perhaps better appi-eciate if we re- 

 call our own j'outh, and remember with 

 what absolute confidence we expected the 

 stray horsehairs we had collected and 

 placed in water to turn into living snakes. 

 The belief that it is an every-day oc- 

 currence for living beings to arise from 

 lifeless matter M'as not by any means 

 confined to those uneducated in biology. 

 It was held by many scientific men within 

 the memory of most of us. Indeed, this 

 goblin of sjiontaneous generation, even for the 

 scientific world, has been laid low so re- 

 cently that the smoke of battle has scarcely 

 yet cleared from the horizon. 



In the complex body of animals, as stated 

 above, the constituent elements perform dif- 

 ferent functions. Is there any hint of the 

 way in which the action is accomplished ? 



Let us glance at two systems, the nervous 

 and the glandular, widely different in 

 structure and function. All know how 

 constantly the glands are called into requi- 

 sition, the salivary glands for saliva, those 

 of the stomach and pancreas for their di- 

 gestive juices, etc. If we take now the 

 pancreas as an example, and that of a liv- 

 ing fasting animal is put under the micro- 

 scopic so that its constituent cells can be 

 observed, it will be seen that they are 

 clouded, their outlines and that of their 

 nuclei being very vague and indistinct. 

 The cell is apparently full of coarse grains. 

 If now the animal is fed, as the digestion 

 proceeds the pancreas pours out its juice. 

 At the same time the granules and with 

 them the cloudiness gradually disappear, 

 the cells become clear and both they and 

 their nuclei are sharply outlined. That is, 

 the substance which is to form the pancre- 

 atic juice is stored in the cells in the form 

 of granules during the periods of rest and 

 held until the digestive agent is demanded, 

 and if the demand is great all the granules 

 may be used up. But as soon as the demand 

 ceases the cells begin again their special 

 vital action, and again the granules begin to 

 appear and increase in number until finally 

 the cells become so full that they are fully 

 charged and again ready to pour forth the 

 digestive fluid. This is a daily, almost an 

 hourly process. Let us take another exam- 

 ple in which there would almost appear an 

 organic memoi-y on the part of the gland 

 cells. ISTo doubt all have seen the clear 

 jelly-like masses surrounding the eggs of 

 frogs and salamanders. Whence comes 

 this jelly that is so resistant to the agents 

 that work so quickly the destruction of or- 

 dinary organic matter '? As spring advances 

 the cells of the oviduct increase enormously 

 in size. The microscope shows this increase 

 to be due to a multitude of clear granules. 

 As the eggs move along, the ova are coated 

 with the jelly formed from the granules 



