28 Structure and Classification of Micro-organisms 



the microscope. These are called " in visible viruses." They are 

 known to us through the biological quality of nitrates in which they 

 are present because of their ability to pass through the pores of the 

 filters. For this reason they are also called "filterable viruses." 

 As they cannot be seen, we have no way of classifying them; they 

 may be bacteria or protozoa, or neither or both. 



TABLE I 



THE PLANT KINGDOM 



2 3 t? These primary divisions, like the cor- 



p,p p responding primary division of animals 



3.5 into vertebrata and invertebrata, are 



ago o now falling into disuse. 



"aHL p 





? fc 

 I 8 





W W w^nONU 1 ^ 



fIRlIf W IIIIIH m 

 r was'i& 



>iyi i! tfiF 



Eir^g 



N N CL .. 



Mr l'f s 



0^ ? & 

 O'S-X-TS 





