STUDY OF POLYNEURITIS GALLINARUM. 445 



hsematoxylin method (Meves, Regaud, Rubaschkiii,(l8) and 

 others) gives the most permanent preparations and is easy of 

 application, it was most frequently employed.^ 



In good preparations of a normal nerve stained by this and 

 the other mitochondria methods, the medullary sheath is seen 

 to contain innumerable little bacilli-like rods. When seen from 

 above, the fiber gives the appearance of containing both rods 

 and granules, but in a fiber which has been split down the 

 middle in sectioning, so that the medullary sheath is seen only 

 on either side of the axis cylinder and not above, only rods 

 are to be observed. These rods arrange themselves in a general 

 radial direction around the axis cylinder, but at places show 

 a more or less X-like crossing. From this it is apparent that 

 the granular appearance is due to an end view of the radially 

 arranged rods. These appearances are identical to similar 

 structures and arrangements described and illustrated by 

 .Nageotte(l9) in the cauda equina of the guinea pig and termed 

 by him mitochondria. Plate VII, fig. 14, is a photomicrograph 

 of an iron-hsematoxylin preparation, and illustrates the arrange- 

 ment and number of these rods in a normal nerve. At a, a! , and 

 a" , the radial arrangement of the rods is shown. This picture is 

 typical of all preparations from the nerves of the 4 normal fowls 

 stained by each of the mitochondria methods mentioned above. 



Fowls 24 and 25, fed for seven days on polished rice, are the 

 earliest on which examinations were made in this series. Fowls 

 were not killed at an earlier period than this, because it was 

 thought that several days must elapse before the normal met- 

 abolic balance of the fowl would be disturbed. Thus in these 

 2 fowls, which serve as a check on each other, we did not expect 



^ The iron-haematoxylin method for staining mitochondria is very simple, 

 easy of application, and well adapted for nerve tissue. It has the further 

 advantage of being permanent and it brings out the rods in sharp contrast. 

 Small pieces are fixed and mordanted in Miiller's fluid two weeks or longer, 

 washed in water (twelve hours), and embedded in paraffine through xylol. 

 Sections, not over 5 microns thick, are mordanted (twelve to twenty-four 

 hours) in 2 per cent iron ammonia alum, washed in water, and stained 

 in Weigert's haematoxylin (for myelin sheath), eight to twenty-four hours 

 in this climate. Differentiate in iron ammonia alum (1 or 2 per cent). 

 Sections sometimes give clearer pictures if immediately before staining 

 they are treated one or two minutes in 0.25 per cent potassium perman- 

 ganate, washed in water, and placed for one or two minutes in Pahl's 

 solution of 0.5 per cent potassium sulphite and 0.5 per cent acid oxalic. 

 For further details on staining mitochondria and other methods, 

 see Altmann,(i6) Bensley,<i2) Benda,(i4) Meves, ds) Regaud, d^) and 

 Rubaschkin.<i8) 



