PROF. EHRENBERG ON THE INFUSORIA. 509 



1. Most (probably all) microscopic animalcula are highly 

 organized animals. 2. They form, according to their struc- 

 ture, two well-defined classes. 3. Their geographical distri- 

 bution in four of the parts of the world follows the same laws 

 as that of other animals. 4. They cause extensive volumes 

 of water to be coloured in different ways, and occasion a pe- 

 culiar phosphorescence of the sea by the light they develope. 

 5. They form a peculiar sort of living earth ; and as 41,000 

 millions of them are often within the volume of one cubic inch, 

 the absolute number of these animalcula is certainly greater 

 than that of all other living creatures taken together ; the ag- 

 gregate volume is even likely to be in favour of the animal- 

 cula. 6. They possess the greatest power of generation known 

 within the range of organic nature ; one individual being able 

 to procreate many millions within a few hours' time. 7. The 

 animalcula form indestructible earths, stones, and rocks, by 

 means of their siliceous testa ; with an admixture of lime or 

 soda they may serve to prepare glass ; they may be used for 

 making floating bricks, which were previously known to the 

 ancients ; they serve as flints, as tripoli, as ochre, for manur- 

 ing land, and for eating, in the shape of mountain meal, which 

 fills the stomach with a harmless stay. They are sometimes 

 injurious by killing fish in ponds, in making clear water tur- 

 bid, and in creating miasma ; but that they give rise to the 

 plague, cholera morbus, and other pestilential diseases, has 

 never been shown in a credible manner. 8. As far as obser- 

 vation goes the animalcula never sleep. 9. They exist as 

 Entozoa in men and animals, the Spermatozoa not being taken 

 into consideration here. 10. They themselves are infested 

 with lice as well as Entozoa, and on the former, again, other 

 parasites have been observed. 11. They are, in general, af- 

 fected by external agents, much in the same manner as the 

 larger organic beings. 12. The microscopic animalcula be- 

 ing extremely light, they are elevated by the weakest currents, 

 and often carried into the atmosphere. 13. Those observers 

 who think they have seen how these minute creatures sud- 

 denly spring from inert matter, have altogether overlooked 

 their complicated structure. 14. It has been found possible 

 to refer to certain limits or organic laws, the wonderful and 

 constant changes of form which some of these animalcula 

 present. 15. That the organism of these animalcula is com- 

 paratively powerful, is evinced by the strength of their teeth 

 and of their apparatus for mastication ; they are also posses- 

 sed of the same mental faculties as other animals. 16. The 

 observation of these microscopic beings has led to a more 

 precise definition of what constitutes an animal, as distinct 



