86 THE POPULAR SCIENCE MONTHLY. 



must refer the reader to Dr. Bastian's work, where the history of re- 

 cent investigations upon the subject is given in detail. 



The growth of new distinctions and more precise ideas in science re- 

 quires the use of new terms to mark them, while, at the same time, old 

 terms have to be discarded, as conveying erroneous ideas. The term 

 " spontaneous generation," although so long applied to the subject, that 

 it will be apt to continue in popular use, has lost its place in biological 

 science, as it is too indefinite, and conveys a false idea. Those who 

 hold that life originates directly from non-living matter do not con- 

 sider that its production in this way is any more truly "spontaneous" 

 than its usual production from parental germs. Several words have 

 been introduced by different writers to define their ideas, which it is 

 desirable here to explain. 



Biogenesis is the term applied by Prof. Huxley to the derivation 

 of life from previously-existing life ; and Abiogenesis to the produc- 

 tion of'life from non-living matter. The latter term, therefore, corre- 

 sponds to what is commonly meant by " spontaneous generation." 



LTomogenesis, or Homogeny, are terms that have been long applied 

 to the production of like from like ; that is, the common case in which 

 the living parent gives rise to offspring which pass through the same 

 changes as itself. 



Heterogenesis, or Heterogeny, is the name applied to processes by 

 which living things arise from the matter of preexisting organisms, 

 belonging to a totally different species. It has, however, had different 

 meanings, and its use has created some obscurity, but it is customary 

 to apply it to the so-called cases of " spontaneous generation ; " and 

 those who hold this doctrine are therefore known as Ileterogenists. 



Panspermy is the name given to the doctrine of diffused atmos- 

 pheric germs, as the sources of infusorial life, and those who hold to 

 this view are called Panspermists. " Spontaneous generation," so 

 called, or the production of living creatures without parentage, may 

 take place in two ways : either from preexisting living matter (hetero- 

 genesis), or from not-living matter. This production of living forms 

 from inorganic materials is termed by Dr. Bastian Archebiosis, which 

 literally means " beginning to live." 



It was in the course of some investigations upon the microscopical 

 characters of the blood of persons suffering from acute diseases that 

 Dr. Bastian's attention was first drawn to the question of the origin 

 of life. He soon became interested in it as an independent scientific 

 problem, and pursued the inquiry experimentally for three years, the 

 results being recorded in the present work. In Part I. he aims to 

 show that the now commonly-accepted doctrine of the Correlation of 

 Forces favors the independent origin of living matter. In this part, 

 also, he has an elaborate chapter showing that the cell cannot be re- 

 garded as the ultimate organic unit. In Part II., under the head of 

 Archebiosis, he takes up the real issue of the spontaneous generation 



