ANNUAL REPORT, 1935 77 



which tends to consolidate either in the infraorbital sinuses and turbinates, or 

 in the trachea and bronchial tubes. Chickens and laying hens affected with 

 colds complicated by any one of these secondary microorganisms are usually 

 out of condition for a period ranging from two weeks to two months. 



Experiments have been conducted in which chickens hatched and reared 

 under strict laboratory conditions were inoculated with cold exudates containing 

 microorganisms isolated from field cases, and the average period of sickness 

 was 40 days. The symptoms were severe in these chickens and some of them 

 died. Similar groups of chickens inoculated with bacteria-free ultrafiltrates 

 of the cold exudate produced mild symptoms of colds. The average period of 

 sickness was only three days, and none of the chickens died. 



Inclusion Bodies in Laryngotracheitis and Golds. (C. S. Gibbs. ) 

 The inclusion bodies in laryngotracheitis are intranuclear, while those in the 

 colds studied up to the present are extranuclear. Considerable variation 

 appears in the shape and form of these bodies at different stages of the disease, 

 indicating that they may undergo some kind of a cycle or growth. Further- 

 more, variation in the particulate size of these bodies, as measured by a graded 

 series of acetic-cellodion membranes, indicates that the size of the inclusion 

 bodies is not always the same. The laryngotracheitis virus particles average 

 less than 0.082 micron in diameter, and the cold inclusion bodies average less 

 than . 135 micron in diameter, although experiments have been conducted in which 

 the particles appeared to be the same size in both cases. Some of this variation 

 may be due to the fact that laryngotracheitis is more virulent than colds, and 

 the respective locations of the inclusion bodies in the epithelial cells of the 

 mucous membrane tend to make the cold virus more readily filterable. 



Differentiation of the Pathological Cell in Neurolymphomatosis 

 from Lymphocytes of the Blood of Chickens. (C. S. Gibbs and C. G. 

 Johnson. ) Unna's eosin and methylene blue stain is modified and successfully 

 used to differentiate pathological cells in neurolymphomatosis from lympho- 

 cytes in smears by substituting Lugol's solution for iodized alcohol and re- 

 ducing the length of time necessary for differentiation in the alcohols. In this 

 way the smears are not washed from the slides and comparative studies of the 

 cells are made under identical conditions — an achievement that has not been 

 accomplished before. With this technique it has been found not only that 

 many of the pathological cells in neurolymphomatosis undergo mitosis, but 

 that the nuclei are more vesicular than the nuclei of the lymphocytes of the 

 blood. 



Fy means of this staining technique cells indistinguishable from those 

 occurring in neurolymphomatosis are found in the follicular fluid of hens, in 

 the semen of roosters, and in the perivascular infiltration in the peripheral 

 nerves of baby chicks produced by affected hens and roosters. While these 

 findings are suggestive that neurolymphomatosis may be transmitted through 

 the egg, the final results are not entirely conclusive because many of these cells 

 are apparently destroyed in the developing embryo by some factor or factors 

 unknown at the present time. 



The Differentiation of Neurolymphomatosis from Lympholeukosis. 



(C. S. Gibbs and C. G. Johnson.) Histological studies indicate that the fowl 

 does not possess lymph glands and lymph nodes anatomically and physiologi- 

 cally comparable to those of higher animals, but does possess relatively large 

 amounts of lymphoid tissue in the bone marrow, liver, spleen and in certain 



