2 \ ^ t&OTISTS AND DISEASE 



phyla, the Protozoa and the Thallophyta, the latter term 

 applying to the algae and fungi, including the diatoms, the 

 desmids, and the bacteria. With Haeckel the Third King- 

 dom was to be that of the Monera, and any non-nucleated 

 cell was to be termed a cytode. 



The question of the Monera was touched upon in 1877 

 by Huxley, but at that date the chromidial state of living 

 organisms was unknown and the data for even a partial 

 solution of the problem were wanting. 



In 1896 the position was summed up judicioiisly by Delage 

 and Herouard : " For a long time great importance was 

 attached to the cytodes and the Monera of Haeckel . . . but 

 it has been found that this supposed absence of a nucleus 

 is explained in many cases by defective methods. Since 

 nuclei have been discovered in the most of the Monera, of 

 the cytodes, and even in bacteria, some people, by rather 

 hasty induction it seems to us, have denied the existence 

 of non-nucleated organisms." Remembering that filtrable 

 organisms, chromidia, and akaryote phases of protists such 

 as Sorosphaera (see Chapter VII) were unknown when the 

 passage just quoted was written, we cannot but admire the 

 moderation of thought and expression shown by the French 

 zoologists. 



The Cell-Theory. A study of protists must include an 

 examination of the cell-theory of life as it exists at present 

 in biology. The nucleus was recognised as a normal feature 

 in the epidermal cells of orchids by Robert Brown in 1833. 



