CHAPTER IV. 



SPONTANEOUS GENERATION. 



THE solution of the yet smouldering, and but a few years since fiercely 

 incandescent, question of " spontaneous generation " is so inextricably bound 

 up with an extensive knowledge and correct appreciation of the vital 

 phenomena of the microscopic beings that form the subject of this volume, 

 that it is felt by the author that a grave error of omission would be com- 

 mitted were not a few pages set apart for its consideration. Spontaneous 

 generation, " generatio tzquivoca" or as it is now more widely designated 

 " abiogenesis," is by no means an invention of to-day or yesterday. It 

 dates back to the classic times of Plutarch, Virgil, and Aristotle, by which 

 three brilliant leaders and expositors of the world's highest wisdom it was 

 seriously maintained that eels grew out of mud, bees from putrefying flesh, 

 and rats through the vitalizing properties of the sun's rays, without any 

 intervening parental agency. Spontaneous generation as enunciated at 

 the present day is the same in essence if not in fact as when evolved and 

 launched upon the seething waters of scientific controversy over two 

 thousand years ago. Then as now, or now as then, the point sought to be 

 established by its exponents was or is, that organic beings can be and are 

 under certain conditions generated or newly created out of dead organic 

 or purely inorganic material, independently of any pre-existent parent, 

 e gg or germ. With the revival of the arts and scientific culture which 

 distinguished the latter half of the seventeenth century, the theory of spon- 

 taneous generation as applied to the grosser forms of animal life, and 

 accepted as an article of creed from the days of antiquity, was attacked 

 and finally disposed of through the labours of such careful investigators 

 as Redi, Reaumur, and Schwammerdam. By the first-named of these 

 authorities, more especially, the maggots found in putrid meat and hitherto 

 supposed to be generated spontaneously, were shown by a combination 

 of careful experiment and inductive reasoning to be the progeny only of 

 flies which had previously deposited their eggs upon it. Reasoning from 

 the constantly observed presence of flies round decaying meat previous 

 to the appearance of the maggots, Redi concluded that these winged insects 

 were the progenitors of the same, and took steps to prove it. Placing meat 

 in a jar and covering it so carefully with paper that flies could not obtain 

 access to it, he found that although putrefaction set in, no maggots were 

 developed, while at the same time these organisms appeared abundantly in 



