The Evolution of Bacteria

Polymorphism is a term used to define the theory which held that bacteria were one of the intermediate shapes or forms between something lower and something higher in the vegetable kingdom. Neither pleomorphism nor polymorphism is fully understood, and many bacteriologists find shelter from both in the term involution form. What we do know is that the species already named take on diverse forms when placed under different conditions. From what we have seen of the diet of microorganisms, we shall conclude that in some form or other, they contain the elements nitrogen, carbon, and hydrogen.