AUTHOR'S DISCOVERY OF GERMS IN 1865. 7 



of these organisms with malarial fever is found in the fact that 

 they are present in the organs, and in the blood of persons who 

 die of marsh fever. 



I found rod-like germs abundantly present in the blood of 

 animals attacked with cattle plague, one of the most intensely 

 infectious diseases that ever visited this country. They are de- 

 lineated in my reports on the subject to the Authorities. So far 

 as I am aware, it was the first time that they were shown to exist 

 in the blood of living animals.* A few facts will better enable 

 you to comprehend the enormous fertility of germs and spores. 



Among the larger animal germs, which are visible to the naked 

 eye, and may therefore be counted, the late Mr Buckland found 

 no fewer than seven millions of eggs in a single cod-fish. The 

 Ascaris, an intestinal worm infesting man and other animals, pro< 

 duces about sixty-four millions of eggs; and in the vegetable 

 kingdom some single plants yield over seventy-four millions of 

 seeds in a season. Numerically great as these figures are, they are 

 dwarfed by the greater productiveness of the spores of some fungus 

 plants. They are inconceivably minute two hundred millions, 

 side by side, would not cover a square inch yet they possess an 

 inherent vitality, which, under favourable circumstances, will burst 

 into life, reproducing the parent plant from which they sprung. 

 Again, we are told that spores, equal in number to the entire 

 inhabitants of the globe, placed side by side, may easily rest on a 

 space four inches square ; and that one million would find ample 

 accommodation on the head of a pin ! 



Professor Tyndall was the first, I think, to make these facts, 

 viz., the presence of particles in the air, palpable to our senses 

 by an experiment which you can all make for yourselves. He 

 let a sunbeam into a darkened room, through a chink or hole 

 in the shutter. The bright ray revealed the floating dust for 

 it is a fact that without dust there would be no visible ray. 

 It is the particles of dust that intercept and scatter the light 

 and make it visible to us. A similar effect is produced when 

 * September, 1865. 



