REDI; TUBERVILLE NEEDHAM. 119 



similar jars of meat left purposely uncovered. Substituting fine gauze for 

 the paper coverings, the flies were soon attracted by the emanating odour, 

 but being unable to get at the meat deposited their eggs upon the gauze, 

 and out of which eggs minute maggots were then seen to develop. This 

 very simple experiment by which Redi proved his case, carries with it, as 

 presently shown, a most practical and important bearing upon the question 

 of spontaneous generation in the modern acceptation of the term. The 

 weapon, however, that proved of the greatest service at about this same 

 epoch in breaking down the ancient superstitions concerning the spontaneous 

 generation of highly organized animals, was undoubtedly the microscope, 

 now utilized for the first time in unravelling the mysteries of nature. 



With this instrument in the hands of Leeuwenhoek, Robert Hooke, 

 Hartsoeker, and other early labourers, it was soon discovered that the hitherto 

 deemed doubtful or spontaneously multiplying species propagated their 

 kind perpetually through the medium of impregnated seeds or eggs, after 

 the manner of the larger and more familiar types, and the idea of spon- 

 taneous generation, so far as such organisms was concerned, was banished 

 to oblivion. The agency, however, which thus achieved the overthrow 

 of this theory in one direction, paved the way for its re-establishment 

 in another, and as it at first seemed, on an apparently far more sure and 

 substantial basis. 



Among the most important revelations of the hitherto invisible and 

 unknown world made known with the assistance of the microscope, was 

 undoubtedly the discovery by Leeuwenhoek, in the year 1676, of the micro- 

 scopic beings that form the subject-matter of this volume. The abundant 

 confirmation of this discovery and the intense interest manifested on all 

 sides in so newly indicated and fascinating a field of research, necessarily 

 entailed a speedy recognition of the extraordinary rapidity with which these 

 minute organisms multiplied, and also of their appearance suddenly in vast 

 numbers under auspices totally at variance with the propagative phenomena 

 of all previously known organic forms. None of the then familiar laws of 

 organic reproduction sufficing to explain these several phenomena, the mind 

 naturally reverted to that interpretation of the "incomprehensible" initiated 

 by the philosophers of antiquity, and stamped such abnormal manifestations 

 with the brand of the miraculous. 



As indicated in a preceding chapter, the theory of abiogenesis or spon- 

 taneous generation, as applied to the minute animalcules produced so 

 abundantly in infusions, took its origin as a possible hypothesis with their 

 first discoverer, and was upheld with more or less force by Gleichen, Joblot, 

 and O. F. Mliller. The first, however, to mould this somewhat vague 

 idea into shape and to formulate out of it that definitive doctrine con- 

 cerning the spontaneous production of the lowest organisms that with 

 varying fortune has commanded adherents thenceforward up to the present 

 time, was undoubtedly our own countryman Tuberville Needham, who in 

 his 'New Microscopical Discoveries,' printed in the year 1745, and various 



