THE PHENOMENA OF LIFE 



"Space contain- 

 ing liquid. 



"""Protoplasm. 



Nucleus. 



Cell wall. 



FIG. i. Vegetable Cells. 



The presence or absence of a cell wall, therefore, was then regarded as 

 quite a secondary matter, while at the same time the cell substance came 

 gradually to be recognized as of primary importance. Many of the lower 

 forms of animal life, the Rhizopoda, were found to consist almost entirely 

 of matter very similar in appearance and chemical composition to the cell 



substance of higher forms; and this from its 

 chemical resemblance to flesh was termed 

 Sarcode by Dujardin. When recognized in 

 vegetable cells it was called Protoplasm by 

 Mulder, while Remak applied the same name 

 to the substance of animal cells. As the 

 presumed formative matter in animal tissues 

 it was termed Blastema, and in the belief that, 

 wherever found, it alone of all substances has 

 to do with generation and nutrition, Beale has 

 named it Germinal matter or Bioplasm. Of 

 these terms the one most in use at the present 

 day as we have already said, is protoplasm, and 

 inasmuch as all life, both in the animal and 

 vegetable kingdoms, is associated with proto- 

 plasm, we are justified in describing it, with 

 Huxley, as the "physical basis of life," or simply "living matter." 



Properties of Protoplasm. Protoplasm is a semifluid substance, 

 which absorbs, but does not mix with water. It is transparent and gener- 

 ally colorless, with refractive index higher than that of water, but lower than 

 that of oil. It is neutral or weakly alkaline in reaction, but may under 

 special circumstances be acid, 

 as, for example, after activity. 

 It undergoes heat coagulation at 

 a temperature of about 54. 5 C. 

 (130 F.), and hence no organ- 

 ism can live when its own tem- 

 perature is raised above that 

 point. It is also coagulated 

 and therefore killed by alcohol, 

 by solutions of many of the 

 metallic -salts, by Strong acids FlG - 2. Semidiagrammatic Representation of 



... a Human Ovum, showing the parts of an animal 



and alkalies, and by many other ce \^ (Cadia.) 



chemical substances. 



Under the microscope it is seen almost universally to be granular, the 

 granules consisting of different substances, albuminous, fatty, or carbo- 

 hydrate matter. The granules are not equally distributed throughout the 

 whole cell mass, as they are sometimes absent from the outer part or layer 



Vitelline mem- 

 brane. 



