According to Vellanskii, this is the Naturphilosophie 

 theory of fertilization. It was possible to establish such 

 a theory because the mammalian ovum was not yet detected, 

 and because the essential content of the Graafian follicle 

 was considered to be the fluid filling it. The demonstration 

 of the presence of the egg or ovum in the Graafian follicle, 

 by K. M. Baer in 1827, made it evident that Naturphilosophie 

 was without grounds with respect to fertilization. 



Turning to the phenomena of embryonic development, 

 Vellanskii gave only the most primitive outline of factual 

 data, since he was interested mainly in repeating the features 

 of ontogenesis which are characteristics for a complex 

 ascending series of animals, i.e. Naturphilosophie 1 s problem 

 of analogy. 



Higher animals, after conception, must pass through 

 all the periods which are characteristic for the 

 development of the lower classes, where they have a 

 prolonged stay in their proper formation. Man, 

 representing the perfect unity of the earthly world, 

 after conception passes through periods which are 

 characteristic of the development of all classes of 

 the animal kingdom; therefore the proper development 

 of his organism is the most prolonged. 30 



The human embryo develops linearly at the beginning 

 into a worm, along which form its membranes reach 

 out . . . ; among them the external membranes 



Cchorion) are highly shaggy. It touches the uterus 

 with its filaments and assumes the fetal place 



(placenta) . The internal membrane (amnion) includes the 

 embryo itself, with its fluid (liquor amnii) . Almost 

 one month after conception the embryo remains invisible; 

 then it appears in a moving spot (punctum saliens) , 

 from which in some days it grows to two and a half 

 millimeters and has the form of a worm. 31 



In the first day, according to Avtenrit, the 

 embryo . . . hangs on a very short umbilical cord . . . 



30. Ibid ., pp. 422 - 423. 



31. Ibid., p. 424. 



158 



