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G. CARL HUBER 



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Fig 1 Oviduct and ovum of albino rat, in 2-cell stage, with first two blasto- 

 meres separated. Rat No. 60, 1 day, 18 hours, after the beginning of insemina- 

 tion. X 200. A, epithelial wall of oviduct with adjacent mucosa, and the fourth 

 of a series of six sections of the 2-cell stage with separated blastomeres, showing 

 them in their relation to the epithelium. B, the series of six sections which 

 pass through the separated blastomeres, the fourth of which is shown in A. 

 The series reads from right to left. 



as shown in B and C of figure 1, Part I. There is here clearly 

 a separation of the first two blastomeres and not a close approxi- 

 mation of two unfertilized ova. In all of the unfertilized ova 

 met with in the oviducts in the series at my disposal, these pre- 

 sent the second maturation spindle and oolemma and are not to 

 be confused with the blastomeres of the 2-cell stage, either as 

 to size or structure. Both of the blastomeres in the prepara- 

 tion under consideration present normal protoplasmic structure, 

 having a finely granular protoplasm. Their nuclei, as may be 

 seen from the figures, are of normal size and structure. They pre- 

 sent regular form, are distinctly membranated, have large chro- 

 matoid nucleoli, and chromatin scattered in fine granules and 

 threads. However, attention needs to be drawn to the presence 

 of two micro-nuclei, one in each of the two blastomeres, showing 

 in the third and fourth section of the series respectively (B, 

 fig. 1). These micro-nuclei are nearly free from chromatin, 

 each presenting a small chromatoid nucleolus. They are not to 

 be regarded as cell inclusions, as perhaps representing phagocytic 

 leucocytes. It may be conjectured that they were formed by 

 amitotic division, by budding and constriction from the parent 



