14 



HtJTCJEHNSON'S POPULAE BOTANY 



FIG. 29. " BLOOD PORTENT " (Micro- 

 coccus prodigiosus). 



A microscopic plant of a single eel 

 about cne-lGOOOth of an inch acr 

 Bacteria. 



lich averages 

 One of the 



a surface no larger than one's thumb- 

 nail. As a rule, indeed, the cells of 

 all Flowering Plants are extremely 

 small, though certain organs may offer 

 remarkable exceptions. Thus the loose 

 cells (pollen-grains) contained in what 

 are known as the anther-lobes of flowers 

 are occasionally of an unusual size, 

 some measuring T Vth of an inch in 

 diameter; though it should be added, 

 as a matter of comparatively recent 

 discovery, that the pollen-grains of a 

 large number of plants are now known 

 to be many-celled. In any case, the 

 size given is exceptional, and fre- 

 quently the grains do not exceed o^Wth 

 of an inch. 



Some of the tiniest organisms 

 visible under the microscope are the unicellular Micrococci (a genus of 

 the Schizomycetes or u fission Fungi "*) spherical plants whose diameters 



vary from ^innmth to T^TTJ^II of an inch 

 (fig. 29) : and along with these may 

 be placed those scarlet river-plants 

 (allied, doubtless, to onr rain-water 

 SphcerellcC), many millions of which, 

 as Freycinet and Turrel tell us, might 

 swim without discomfiture in a drop 

 of water ! The Schizomycetes form 

 an interesting group, for they include 

 the Bacteria, Bacilli, and other formid- 

 able organisms, to which many of the 

 deadliest diseases are known to be 

 due.f The microscope has revealed 

 no minuter organisms than these. 

 Countless thousands of the dreaded 

 Kitasato bacillus (fig. 26), which is 

 parasitic in the human body and 



* So called because they multiply by a simple 

 division of the body. 



t Bacillus antkracis is the probable cause 

 of anthrax in cattle, etc. ; B. tuberculosis of 

 consumption ; Spirochoete cholera? asiaticas of 

 Asiatic cholera (fig. 25) ; and various other 

 species of bacteria are associated with leprosy, 

 relapsing typhus, footrot, etc. 



FIG 30. CORK CELLS. 



The separate ceils may be seen easily in this photo but 



they are shown 125 times larger than the natural size. 



