THE LARGE GROUP OF THE SMALLEST ORGANISMS 167 



sunlight while in animal cells, food is made outside and has to be 

 absorbed before it can be used. The method of nutrition used by the 

 green plant is called holophytic, and that of the animal cells, holozoic. 

 The differences between these two types of nutrition are summed up 

 in the table below. 



SUGGESTED READINGS 



Calkins, G. N., Biology of the Protozoa, Lea & Febiger, 1926. Chs. I, III, 



and IV, especially. 

 Dobell, C., Antony van Leeuwenhoek and his "Little Animals," Harcourt, Brace 



and Co., 1932. 



The entire book, which contains excellent translations of most of the 



original letters of van Leeuwenhoek, is well worth reading. It is a 



most authentic picture of this interesting Dutchman and his times. 

 Giltner, W., Textbook of General Microbiology, P. Blakiston's Son & Co., 1928. 



Ch. III. 

 Holman, R. M., and Robbins, W. W., Elements of Botany, 3rd cd., John 



Wiley & Sons, Inc., 193(3. Ch. X. 

 Locy, W. A., Biology and Its Makers, Henry Holt & Co., 1908. Ch. V. 



An excellent historical survey. 

 Needham, J. G., and Lloyd, J. T., Life of Inland Waters, 2nd ed. Charles C. 



Thomas, 1930. Ch. IV. 



Excellent descriptions and illustrations of the life found in pond water. 

 Singer, C. J., The Story of Living Things, Harper & Bros., 1931. Ch. IV. 



An interesting and authentic history of biology. 

 Ward, H. B., and Whipple, G. C, Fresh-Water Biology, John Wiley & Sons, 



Inc., 1918. 



This book is invaluable for reference. Chapters VI, IX, and XVII arc 



especially useful. 



H. w. H. 



12 



