354 



PLATE VI 



Fig. 1. Foam prepared from olive oil and NaCl. A small part of the mesh- 

 work. Camera lucida, x 1800. 



Fig. 2, a-b. Foam prepared from very much thickened olive oil and K 2 C0 3 ; 

 very viscid. Drawn out by compression of the cover glass into strands, 

 which show the fibrillated alveolar structure very beautifully. 2 a, a 

 strand with low magnification. 2 b, a small part of this strand with 

 greater magnification, showing the honeycombed structure distinctly. 



Fig. 3. Lumbricus tcrrestris L. Longitudinal section through a supporting 

 cell of the epidermis. Iodine-alcohol, acid htematoxylin, damar. 

 c, cuticle. In the nucleus the framework, stained blue, is very distinct, 

 with red chromatin granules lodged in it, and a nucleolus similarly 

 stained. In the meshwork of the protoplasm there are similarly 

 stained red granules, which, however, are smaller, and hence more 

 difficult to observe. 



Fig. 4. A small portion of a cell from the fat body of Blatta oricntalis L. 

 Stained by Gram's method, with subsequent staining with vesuvin. The 

 large cavities (/) have arisen by fat drops becoming dissolved, b, the 

 vividly stained Bacteroids, which are distinctly lodged in the pale mesh- 

 work of the protoplasmic bridges. 



Fig. 5. Optical section through the epidermis (margin) of a living gill lamella 

 of Gammarus pulex de G. c, cuticle. The striated alveolar structure of 

 the protoplasm can be distinctly recognised. 



