so 



BIOLOGY OF THE PROTOZOA 



Further work on these different types of lipoidal elements of the 

 cytoplasm of Protozoa is much needed and a more critical classifi- 

 cation of the formed structures of the cell is greatly to be desired, 

 particularly in connection with chromidia, parabasals, mitochondria 

 and Golgi bodies. 



5. Silver Line System.— Recent technical developments have led 

 to the discovery of a complex system of fibrils in the cortex of ciliates. 

 The way was paved for this by observations of Bresslau (1921) who 





m 



jMftf!! ; 



Fig. 41. Fig. 42. 



Fig. 41. — The silver line system of Discomorpha pectinata. Right side. (After 

 Klein, Arch. f. Protistenkunde, courtesy of G. Fischer.) 



Fig. 42. — The silver line system of Discomorpha pectinata. Left side. (After 

 Klein, Arch. f. Protistenkunde, courtesy of G. Fischer.) 



endeavored to find some chemical (stain) which would cause imme- 

 diate coagulation of the colloidal structures, especially of the cortex. 

 He used a mixture of equal parts of a 10 per cent opal blue stain 

 and of 6.5 per cent phloxin-rhodamin stain. Ciliates were allowed 

 to dry in this mixture and were then mounted in balsam. Success- 

 ful preparations made in this way revealed specific types of cortical 

 markings of rectangular or rhomboidal shape. Here areas of 

 coagulation gave evidence of more or less definite boundaries. 



B. Klein (1926) also used the method of drying, but drying with- 

 out coagulation. He argued that small organisms may lose their 



