PROTOZOA 195 



Staining. The organism requires special staining, and a 

 number of complicated methods have been introduced by 

 different investigators. The Giemsa stain is said to give the 

 best results. (See Staining Fluids, p. 35-) 



The slide is fixed, dried in air, hardened in absolute alcohol 

 twenty-five minutes, stained with dilute stain (i drop to i c.c. 

 of water) for ten minutes, washed in water, and mounted. 



In tissues the organism can be shown by fixing with silver 

 nitrate after the manner of Ramon y Cajal. The tissue is 

 (i) Hardened in formalin for twenty-four hours (the sections 

 should be thin) ; (2) washed in water for one hour; (3) alcohol, 

 twenty-four hours; (4) i^ per cent, silver nitrate solution in 

 incubator at 37 C. three days; (5) washed in water twenty 

 minutes; (6) placed in mixture of pyrogallic acid, 4 parts; for- 

 malin, 5 parts; distilled water, to make 100 parts, and kept in 

 dark bottle for forty-eight hours; (7) washed in water and 

 alcohol and then embedded in paraffin and sectioned. Spiro- 

 chaetae black, tissues, pale yellow. Or counterstain of fuchsin 

 can be employed. 



Transmission. Metchnikoff and Roux have inoculated 

 anthropoid apes, producing in them the primary sore and 

 secondary symptoms, with reproduction of the organism. 

 There is no increase in the blood. All facts point to this 

 organism as being the true cause of syphilis. 



Classification. It is undecided whether the spirochaete of 

 syphilis belongs to the group of bacteria known as spirilla or 

 to the protozoa. 



Amoeba Dysenteriae. Found in the intestinal ulcers, feces, 

 and secondary liver abscesses in certain cases of dysentery. A 

 non-pathogenic form, Amoeba coli, also occurs. The Amoeba 

 dysenteriae is a unicellular animal organism, measuring 25 to 

 35 fj. in diameter, though larger and smaller forms occur. There 

 are a nucleus and a nucleolus; the protoplasm of the cell-body 

 is vacuolated, and often contains red blood-cells and bacteria. 

 In fresh, warm stools active ameboid motion may be observed. 

 The non-pathogenic form is smaller and never contains red 

 blood-cells. 



