INCLUSIONS IN EGG OF ECHINARACHNIUS 479 



sometimes the inside distinctly took the pink aUzarin stain. 

 This is interpreted as showing the formation of the nutritive 

 plates, or yolk, from mitochondria. The nutritive material 

 accumulates at the center and increases until it is nearly as large 

 as one of the numerous yolk plates. When this occurs the mito- 

 chondrial remnant is found as a delicate violet rim around the 

 surface of the plate, or there may be in addition a larger bit of 

 the violet-stained material clinging to one side. 



There have thus been followed the fat drops which are emulsi- 

 fied into minute fat droplets and are distributed through the cyto- 

 plasm where they are probably transformed by some kind of 

 synthesis into mitochondria. These mitochondria in turn build 

 up within themselves the large nutritive plates which furnish 

 energy for the cleavage processes. The line which is drawn be- 

 tween active and inactive inclusions is, in the case of the egg of 

 Echinarachnius parma, purely arbitrary. All transitional stages 

 between deutoplasmic granules like fat, and mitochondria have 

 been demonstrated. 



C. Precipitations 



After the use of picro-acetic and sublimate-acetic fixatives, 

 striking bodies which stain strongly in iron hematoxylin are found 

 in the cytoplasm. These are the large black masses surrounded 

 by clear areas shown in figure 7. They are invariably at the 

 centers of open spaces, which leads to the conclusion that they 

 are condensed or precipitated from material once occupying the 

 entire space. After fixation in sublimate-acetic they tend to 

 assume a sHghtly more elongated form than after picro-acetic as 

 figured. Such irregular precipitations are found in all unfertilized 

 eggs fixed either in picro-acetic or sublimate-acetic. Proof that 

 eggs containing them are normal is found in the subsequent 

 history of some series where practically 100 per cent development 

 followed fertilization. It may be argued that these precipitations 

 are the result of the action of the fixing fluids, since, as has been 

 pointed out by Mathews (Physiological Chemistry, p. 120 and 

 p. 1086), the salts of metals and picric acid have the power to 

 precipitate proteins. The following facts prove that this cannot 



