BY WILLIAM J. BYRAM. 



11 



A speck of grey, truly, but that speck in itself a labyrinth of 

 matter, a laboratory of chemical activities utterly baffling in their 

 bewildering complexity. Bearing in mind then that remarks 

 about the homogeneity of protoplasm and the structureless 

 nature of the cell are defective, let us pass on to scrutinize some 

 further examples of cells. Turning back to our microscope, we 

 shall not unlikely observe a whitish-grey spherical body, rayed 

 like the small diagrams of the sun given in the text books of 

 physical geography. This is the sun-animalcule, or actinophrys 

 sol, as it is called scientifically, an organism very little higher in 

 the scale of being than the amoeba. It consists of but a single 

 cell, a speck of protoplasm, which contains in its interior a 

 number of empty spaces or vacuoles. At one side is a remarkable 

 round space, which opens and closes with a regular rythmic 

 pulsation like a minute colourless heart ; this space, known as 

 the pulsating or contractile vacuole, which we also saw in the 

 amoeba, seems to indicate a kind of rudimentary respiration. 

 The water in which the sun-animalcule and amoeba live has 

 oxygen gas dissolved in it, and through the contractile vacuole 

 the oxygenated water is distributed through the various spaces 

 of the cell. The amoeba and the sun-animalcule cannot live in 

 water which has been boiled, and from which consequently all 

 the oxygen has been expelled, and if we keep the cover glass of 

 the live cage upon them they become languid, and afterwards 

 break to pieces. There is, therefore, certainly a process of 

 respiration. The sun-animalcule feeds and reproduces by sub- 

 division in the same simple way as the amoeba. And here again 

 the subdividing process cannot go on indefinitely, for occasionally 

 there is a union of two individuals as a prelude to increased 

 powers of subdivision. How wonderful that all the essential 

 vital functions should be present in that minute jelly speck ! 

 Having no stomach, it feeds and digests ; having no respiratory 

 apparatus, it performs the equivalent of breathing ; having no 

 nerves, it feels the slightest touch of any small creature that 

 strikes its rays, for they bend together at the contact ; having no 

 eyes, it is so sensitive to light that it will shift to the side of a 

 glass trough which is illuminated by a sunbeam. 



Leaving the sun-animalcule, we take a little fresh yeast 

 which we have obtained from our baker and examine it under 

 the microscope. With a high power we find that it consists of a 



