the fetus is equal in size to a bee; its head is large in 

 comparison to the body. Next to the mouth the eyes are visible, 

 but there is still no trace of the nose. On each side, near 

 the corners of the mouth, is seen a very small opening, which 

 is the future aural canal; the extremities are short and thick, 

 the upper are developed more than the lower; the fingers on 

 these and the others are rudimentary. Between the end of the 

 second and the beginning of the third month, the size of the 

 embryo is about two Parisian inches; the forehead is rounded; 

 the eyes are closed; the nose shows up; the mouth is closed; 

 the lips are not yet turned back; the digits of the hands and 

 feet are in the form of distinct rudiments. Between the tenth 

 and eleventh weeks the umbilical vessels are strongly twisted 

 and yet there is no trace of the placenta, which appears 

 between the twelfth and sixteenth weeks of pregnancy. The 

 second stage of development of the fetal membranes occurs in 

 this period, and in particular the disintegrating membrane 

 appears and the vessels outside the embryo aggregate in one 

 spot. The amniotic fluid increasingly accumulates and becomes 

 non-transparent, resembling milky serum. 



Pavlov skipped the descriptive details of the fetal 

 ovum's structure and cited "the brilliant work of the famous 

 professor J. Wenssowitsch (43) , entitled, 'On the Structure 

 and Role of the Fetal Membranes and Placenta.'" 37 Next, Pavlov 

 considered the processes of fetal growth, denoting that in 

 different periods of life the rate of growth is not the same; 

 it becomes slower with the approach of the moment of birth. 

 The increase in body size of all living creatures is a result 

 of nutrition; the same thing relates to the fetus growing in 

 the uterus. "From ancient times," Pavlov wrote, "the question 

 of how the fetus feeds was raised; this question was solved 

 differently in different times, because each school of 

 physiologists had its own hypotheses" ($ 23) . 



These words represent a transition to the second chapter, 

 "Investigation of Opinions about the Nutrition of the Human 



37. (Joannes Wenssowitsch) , DISSERTATIO OBSTETRICIO- 

 MEDICA DE STRUCTURA ET USU SECONDINARUM, QUAM 

 . . . PRO GRADU DOCTORIS IN AUDITORIO MAJORE 

 UNIVERSITATIS CAES. Moscow, 1803, 65 pp. 



163 



