54 Proceedings of the Royal Irish Academy. 



of being taken captive by the pigmy inhabitants, he assumed kingly state. 

 " He was king for a day, and he has left us his kingdom for ever." 



IV. 



We can say that before every great discovery a period of myth and 

 superstition existed in which the natural events are interpreted by allegory 

 or empirical dogma. Later on, when science possesses some of the necessary 

 implements of knowledge, there are numerous tentative speculations 

 advanced— speculations which are frequently incorrect because the means 

 employed are inadequate to meet the difficulties of the investigation, or 

 because the problem is very complex and requires a preliminary process of 

 analysis. The inquiry into the origin and nature of micro-organisms is 

 probably the besi example of this gradual emergence of scientific knowledge 

 from unscientific speculation. 



The mathematician and alchemist Athauasius Kireher (16-41) is generally 

 credited with the first rational presentation of the belief in a world of 

 invisible living organisms influencing the material welfare of men and lower 

 animals : 



" It is so true that the air, the water, the earth, all swarm with 

 innumerable very minute insects, that now-a-days it can be proved by 

 the human eye. It lias been universally known that worms are 

 produced in putrifying bodies : but only since the wonderful invention of 

 the microscope Kas it been possible to recognize that all putrifying 

 substances teem with an innumerable swarm of beings invisible to the 

 naked eye." 



The opinions of Father Kireher were accepted by the great naturalist 

 Linnaeus and by his pupil Nyssander, who made them the basis of a germ 

 theory of disease ; according to which each infective disease was due to a 

 particular micro-organism or germ. This is all the more interesting as it was 

 formulated iu the entire absence of any precise experimental proof. 



A tremendous controversy slowly developed as to the existence and 

 significance of micro-organic life. Good experimental work and bad 

 reasoning joined issue with unsound investigation and brilliant guess-work. 

 Some seekers denied completely the very existence of these germs ; others, 

 with a touch like King Midas of old, found them wherever they chose to lay 

 their hands. The controversy was still further obscured by acrimonious 



