116 OVULATION AND EGG TRANSPORT 



d. That the female body cavity is extensively lined with ciliated epithelium can be 

 further demonstrated by excising a portion of the liver and placing it on a micro- 

 scopic slide in some Standard Solution. Using direct and reflected lighting and 

 low power magnification it will be possible to observe the surface and the edge of 

 this piece of liver for evidences of ciliary currents and cilia. As the surface 

 becomes slightly dried it will be possible to observe fields of cilia, rather un- 

 evenly distributed. A thin strip of the edge of the liver placed under a cover- 

 slip and examined with transmitted light under high power magnification will show 

 the continuous action of marginal cilia. Similarly examine the liver of the male 

 frog. The presence of cilia may be considered as a secondary sexual character of 

 female frogs. 



THE OVIDUCTS ■ 



The oviducts of this ovulating female should be filled with eggs. Observe a single 

 egg through the walls of the oviduct as it is being propelled toward the uterus. The egg 

 will be seen to rotate (spirally) within the oviduct at the rate of about one complete 

 turn in Ik seconds. Does the next egg In line rotate in the same direction? What is the 

 cause of rotation? 



Since the body cavity eggs cannot be fertilized and will not cleave, It is of inter- 

 est to find where this change in fertllizability occurs. Arrange finger bowls with con- 

 centrated sperm suspension, made up of 2 testes per 10 cc. of Standard Solution, and label 

 the bowls as follows : 



a. Uppdr third of oviduct 



b. Middle third of oviduct 



c. Lower third of oviduct 



d. Uterus 



Tie a piece of cotton thread (or dental floss) around the uterus at its upper ex- 

 tremity, at the point of Junction with the oviduct. Similarly tie a thread around the 

 lower limit of the uterus after separating the two uteri. Then excise the entire oviduct 

 and keep It moist with Standard Solution. Cut the oviduct into thirds and silt each sec- 

 tion open and shell out the eggs (with the aid of forceps) into the appropriately marked 

 finger bowl. To get a sufficient niunber of eggs both oviducts may be used. Treat the 

 fertilized ovlducal eggs in the normal manner and observe for: 



a. Percentage cleavage and nonnality of development. 



b. Amount and arrangement of the Jelly on eggs from different levels of the 

 oviduct. 



The eggs in the uterine sac are presumably normal and can be expelled into a normal 

 sperm suspension as control eggs for the above observations. These eggs are all in meta- 

 phase of the second maturation division and are excellent material for physiological ex- 

 periments. 



The above observations will consume several hours of time but can all be made on a 

 single ovulating frog if the tissues are kept moist in appropriate Standard Solution and 

 are not allowed to become overheated. 



OBSERVATIONS AND TABULATION OF DATA : 



a. A complete description of the rupture and the emergence of the egg from its 

 follicle should be made and compared with descriptions for the same process in 

 mammals . 



b. The relationship of ovarian movements should be determined by comparing such 

 movements with those in a non-ovulating ovary. 



c. Analysis of the effects of insemination of body cavity eggs should be made and 

 should be supplemented with a cytologlcal study using both Heidenhain's Iron- 

 haematoxylln and Feulgen techniques. 



