72 MISSOURI BOTANICAL GARDEN. 



The lowest organisms whose life history oas been followed 

 under the microscope, arc bacteria. Plants, in their rela- 

 tionships, these minute beings, which are so small that m;iny 

 billions of some of the species could be brought within the 

 space of a cubic inch, resemble animals in so far that they 

 can derive their food only from organic matter; and in 

 doing this they cause some of the most striking phenomena 

 known to science. The decay of a piece of meat or an 

 egg, the souwng of a glass of milk, are so familiar to us 

 that we accept them as realities without inquiring as to their 

 cause. Modern science shows that these changes, in short, 

 all that we commonly know as putrefaction or decay, are 

 due to the development within the putrefying substance of 

 myriads of bacteria; the malodorous and poisonous pro- 

 ducts that accompany decay being merely the waste matter 

 excreted by them. 



Bacteria are omnipresent. Wherever the path of a ray 

 of sunlight can be seen in the air of a darkened room they 

 exist. Wherever dust collects they are to be found. 

 Dampness favors their propagation. Drought aids their 

 dissemination. Throughout the universe nothing is more 

 widely distributed, unless it be air. If these agents, small 

 in themselves, but capable in the aggregate of producino- 

 so great effects, were confined to dead matter, they might 

 not be entirely without merit. Disagreeable as decomposi- 

 tion may be in many of its manifestations, and harmful as 

 it is in much of our every-day life, much that is worthless 

 and unsightly is rapidly returned by it to begin the round 

 of existence anew. The rancid change in butter may be 

 unpleasant, but without essentially the same change cheese 

 Avould not ripen from the curd. The souring of cider may 

 please the taste of the veteran only, but without it our 

 tables would be destitute of vinegar. If the results ob- 

 tained by Schloesing and Muntz are to be accepted, the 

 vegetation of the trees which shade our streets, the flowers 

 with which our parks are adorned, and even the grass on 

 which our cattle feed and the crops upon which we directly 



