ANIMALCULAE LIFE. 145 



broken beds, over many degrees of terrestrial surface. If man is 

 destined to inliabit the earth much longer, and to advance in nat- 

 m-al knowledge with the rapidity which has marked his progress 

 in j^hysical science for the last two or three centuries, he will 

 learn to put a wiser estimate on the works of creation, and will 

 derive not only great instruction from studying the ways of 

 nature in her obscurest, humblest walks, but great material ad- 

 vantage from stimulating her productive energies in provinces 

 of her empire hitherto regarded as forever inaccessible, utterly 

 barren.* 



* The fermentation of liquids, and in many cases the decomposition of semi- 

 solids, formerly supposed to be owing purely to chemical action, are now 

 ascribed by many chemists to vital processes of living minute organisms, both 

 vegetable and animal, and consequently to physiological as well as to chemical 

 forces. Even alcohol is stated to be an animal product. The whole subject 

 of auimalcular, or rather minute organic, life, has assumed a new and start- 

 ling importance from the recent researches of Pasteur and other naturahsts 

 and physiologists into the agency of such life, vegetable or animal, in exciting 

 and communicating malignant and contagious diseases, and it is extremely 

 probable that what are vaguely called germs, to whichever of the organic 

 kingdoms they may be assigned, creatures inhabiting various media, and 

 capable of propagating their kind and rapidly multiplying, are the true seeds 

 of infection and death in the maladies now called zymotic, as well perhaps as 

 in many others. The very late investigations of Kock into tubercular dis- 

 eases, which, according to the announcement in the Berliner Klinisehe Woclien- 

 schrift, April 10th, 1882, have resulted in the most important discovery of the 

 Bacillus tuberculosus, and the suggestions of physiologists with regard to the 

 possibility of mitigating, by means of inoculation, the virulence of other 

 diseases besides the small-pox, are of vital interest to humanity. 



The literature of this subject is now very voluminous. For observations 

 with high microscopic power on this subject, see Beale, Disease Germs, their 

 supposed Nature, and Disease Oerms, their real Nature, both published in 

 London in 1870. 



The increased frequency of typhoidal, zymotic and malarious diseases in 

 some parts of the United States, and the now common occurrence of some of 

 them in districts where they were unknown forty years ago, are startling facts, 

 and it is a very interesting question how far man's acts or neglects may have 

 occasioned the change. See Third Annual Report of Massachusetts State 

 Board of Health for 1873. The causes and remedies of the insalubrity of 

 Rome and its environs have been for some time the object of careful investi- 

 gation, and many valuable reports have been published on the subject. 

 Among the most recent of these are : Relazione suite condizioni agrarie ed 

 igieniche della Campagna di Roma, per Raff able Pareto ; Cenni Storici 

 sulla questione delV Agro Romano di G. GtrERZONi ; Cenni sulle condizioni 

 Fisicoeconomiclie di Roma per F. Giokdano ; and a very important paper in 

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