10 EASY LESSONS IN YsGErABLE BIOLOGY. 



matter ; a gas, or ethereal vapor. Heat, oxygen, and 

 galvanism have all had their advocates, and at the 

 present day, when teachers of physical science show 

 that one kind of force (as motion, light, heat, or elec- 

 tricity) can be converted, or changed, into another, 

 some are found to say that physical force can be 

 changed into life, or vital force. But this theory is 

 insufficient to explain what life is, since it does not 

 show what is meant by " physical force," nor what 

 changes its form. Life must either be the power of 

 matter or spirit, for we can only conceive of these two 

 forms of existence. This theory is also insufficient, 

 since it does not account for the living germ through 

 which (according to the theory) heat or other form of 

 force passes in order to be converted into vitality. 



6. Writers who have endeavored to define life in 

 accordance with the teaching of materialism which 

 makes matter explain every thing have involved 

 themselves in unsatisfactory and often absurd con- 

 clusions. The teaching of the Bible and of all the re- 

 ligions of mankind, the belief of the most eminent 

 philosophers, the doctrine held by the early Christian 

 fathers, and maintained by the majority of scientific 

 and unscientific men, is that the difference between a 

 living body and the same body after death arises from 

 the union of matter and spirit. In other words, a 

 living thing is a spiritual essence which clothes itself 

 with material particles after a form and according to 



