292 J. S. FERGUSON 



The accurate and shai-p delineation possible under lii^h inaj2;ni- 

 fication between the opaque black fibrils and the liglit brown 

 protoplasm of the cells presents appearances in thin sections which 

 seem to me to show unmistakably that some portions of the fi- 

 brils are certainly contained within the cytoplasm of fixed connec- 

 tive tissue cells. I do not find any such condition in relation to 

 the lymphocytes which are so numerous in the same vicinity. 

 In fig. 10 the fibrils a are, in the case of the lowTr cell at least, cer- 

 tainly outside the cell at one point, viz., where it ends by passing 

 out of the plane of the section. But at the point b each fiber 

 makes a distinct loop which can be followed by change of focus. 

 The granular cytoplasm forms a continuous mass but in the mid- 

 portion of the loop it can be distinctly seen at a level above that of 

 the fiber; w^hile at the ends of the loop, in fact at all the solid black 

 portions of the fiber the cytoplasm is distinctly below the fiber. 

 It would appear obvious that each fiber has penetrated the cell 

 and must, therefore, during its passage have been found within 

 the cytoplasm. Fig. 10 was drawn from a section of the spleen, 

 but in fig. 11, which is from a lymphatic gland and in which a 

 again marks the portion of the fiber above, and b that below the 

 cytoplasm, the same condition holds. Such places are extremely 

 abundant, and in thin sections of all the lymphoid tissues ex- 

 amined they can be found with ease, often several in a single 

 field. Again in transections of the coarser fibers, or in oblique 

 sections, the fibers are often seen surrounded on all sides by a 

 light brown halo of cytoplasm. Such appearances are indicated 

 by fig. 9, though it is difficult to depict them accurately even with 

 the aid of the camera lucida because of the extreme fineness of the 

 fibers and the very thin cytoplasmic coat (represented by the 

 stipling) by which they are surrounded. The cut ends of most of 

 the transversely and obliquely cut fibers show the halo of cyto- 

 plasm in the actual sections. 



The above observations appear to show convincingly that, at 

 least, at times the fibrils lie distinctly within the cells. That they 

 may be so found, as also without the cells, is in harmony with 

 Mall's suggestion as to the ontogenetic relationship of "reticu- 

 lum" and other connective tissues since he supposes this tissue 



