536 FOOT AND STROBELL. [Vol. XVII. 



after treatment with sodium chloride. The preparations show- 

 aggregations of the author's " cyanoplasm." These aggrega- 

 tions are described as " collections of granules of deeply 

 staining cyanoplasm." Later, however, Morgan states that " the 

 granular effect is due only in part to granular structure. The 

 cyanoplasm appears to be made up of groups of alveoli. Possi- 

 bly it is only a network. ... It corresponds probably to 

 Boveri's archoplasm, and if so the latter cannot be looked upon 

 as a specific substance in the cell. . . . An accumulation of 

 deep blue cyanoplasm is present both in normal eggs and in 

 those from the salt solution around the polar spindle. . . . 

 This cyanoplasm forms the clear polar area of the living ^%^y 

 A comparison of these figures with our Photos 5 1-59, PL XLIII, 

 indicates that these aggregations of cyanoplasm are compa- 

 rable to the aggregations of archoplasm in the egg of Allolo- 

 bophora. Whether the latter are artefacts we can hope to 

 decide only by a careful comparison of the distribution of the 

 substance after a variety of fixatives. A study of artificial 

 (perhaps exaggerated) aggregations of the substance should 

 aid the cytologist in determining whether such aggregations 

 are merely condensations of the network substance, or whether 

 they demonstrate the presence of an individual constituent of 

 the cytoplasm. Our preparations indicate that a network can 

 be formed without any contribution from the archoj^lasm, and 

 that therefore the two substances represent individual con- 

 stituents of the cytoplasm. See p. 529. 



Photographic TecJiniqiie. — Plates, Carbutt (New Process or 

 Carbutt B-16) and Hydrochinon developer, according to the 

 formula recommended for these plates. When necessary, the 

 negatives were intensified. Our method of focusing has been 

 described in an earlier paper (12). 



To ascertain at a glance whether the focus has slipped 

 during the interval of rest ^ a very simple device has been 

 found helpful. After determining the exact focus desired for 

 the detail to be photographed, select at least two microsomes 



1 " Let the microscope stand undisturbed for at least ten minutes before pulling 

 down the camera, and never attempt to take a photograph unless the focus has 

 held absolutely true during this interval" (12), p. 613. 



