Marvels of the Universe 331 



leaves. Bacteria, however, have no cells containing chlorophj'll, and so. being totally de\-oid of 

 this substance, must necessarily obtain their carbon elsewhere. It therefore follows that Bacteria 

 are seldom able to lead a " free life," depending 



to a greater or less e.xtent on living or dead 



%." 



^'V 



/.(•(/: 



Structures for their food. Hence, the majoritv of 



Bacteria are parasitic {i.e., preying on living 



matter) or saprophytic (living on dead matter). 



It was parti}' this total absence of chlorophvll 



that led many to think that Bacteria should be 



placed rather in the animal than in the vegetable 



kingdom. But in totalling up their respective 



animal and vegetable-like characters no doubt 



remained that Bacteria were more like a verv low «■ ^^ri 



form of plant. This conclusion caused much ' S- v"^ m,- -^" ^^ 



astonishment to those well-informed people who 



had considered Bacteria a species of cheese-mite. 



Although about four-fifths of the air is nitrogen, 

 yet the higher plants are contin\ially suffering 

 from a nitrogen famine, because they have no 



means of "tapping" the atmosphere: and they I'lmiohyiH-rmhsionnf] [,i/<..< 



depend, except in a few cases, on the soil for t\phoid. 



n, . ^ , . „ . . ^ The germs of Typhoid as they appear under a high 



the nitrogen they obtam. Certam species of „„„,, „f .^e „,icroscope. They are magnified about 



Bacteria, however, have the power of obtaining twelve hundred times. 



nitrogen from the air, and do so either independently or else in partnership with plants, such as 



beans and peas, little aware that by so doing they are signing their own death-warrant. For the 



plant, in obtaining the nitrogen from the Bacteria, is unscrupulous enough to devour the rightful 



owner. It is easy, therefore, to understand the 



vast importance of the nitrogen-fixing organisms 



to the plant world, and indirectly to man. '^" I i 



It is interesting to know that Bacteria vary ^ 



greatly in size, from .3 of a micron to 30 or more °C -• 



microns in length ; a micron ( ) being one twenty- * ^ ** J ^ %m 



five-thousandth of an inch. In a few cases the 



individuals of the same species are not constant 



as to size. The Tvphoid Bacillus, although 



usually a rod 2 to 3 fi long and .6 fi broad, 



occasionally occurs as a much larger and broader 



organism, 10 or even 20 /j long and 2 n thick. --^iLt. .« ^ ' ^ / 



The Comma Bacillus, so called because it some- ' -# 



what resembles a comma, is a minute curved rod mm tr'^L ^ t 



one twenty-five-thousandth of an inch long, and i,A^, 



is responsible for the disease known as Asiatic % 



Cholera. It is interesting to know that the y 



Comma Bacilli are able to live for several months j-ii„(„i,,, ,,ermh.uc,nnr] [Mi-sxrs Leu^ 



in polluted water, whilst in distilled or very pure Asiatic cholera, 



water theV rapidl}' die ; in fact, seldom remain This organism is commonly known as the Comma 



., ^ ^ f. .. Bacillus from its often assuming a curved form. 



alive for longer than twenty-four hours. 



The Tubercle Bacillus, the germ responsible for consumption, is from 3 to 5 ^ long. It is 

 difficult— in fact, impossible— to realize what vast or exceedingly minute sizes represent. A simple 



y ^ ., 'At • > 



