NEUROLYMPHOMATOSIS 27 



Up to this time no evidence had been secured to indicate that hens and 

 roosters with neurolymphomatosis of the eyes transmitted the disease to their 

 chickens as long as the ovaries and testes were unaffected. Hen E-1025, in 

 the third mating, was three years old and the ciliary nerves of the left eye were 

 paralyzed so that the bird was totally blind in this eye. This hen was on the 

 1934 and 1935 experiment for the transmission of neurolymphomatosis through 

 the egg (Table 10). While on this experiment she laid 200 eggs from which 120 

 healthy chickens were hatched, and none of them showed symptoms of neuro- 

 lymphomatosis over a period of eight months. In this control experiment she 

 was mated to a yearling rooster, O-1063, with the same affection of the left 

 eye. Unfortunately her egg record for this last mating was not kept; but it 

 is known that 17 healthy chickens were hatched, six of which developed 

 neurolymphomatosis over a period of four months. Three of the chickens had 

 neurolymphomatosis of one eye, two of both eyes, and one of the mesenteric 

 nerve. At necropsy hen E-1025 showed a small neurolymphoma embedded 

 in the ovary, and the coeliac plexus was unaffected. This ovarian lesion may 

 have been responsible for the transmission of the disease to the chickens, al- 

 though at no time during the course of this investigation were neurolympho- 

 matous cells found in the follicular and seminal fluids of any of the controls. 

 The fact that five of the six affected chickens had neurolymphomatosis of the 

 ciliary nerves like the parents may indicate that some unknown inheritable 

 factors operated in addition to the actual transmission of the pathological cell 

 through the egg. 



These matings produce further evidence to indicate that neurolymphomatosis 

 is transmitted through the egg to the chick, and that cells indistinguishable 

 from the pathological cells in neurolymphomatosis sometimes appear in the 

 follicular and seminal fluids of affected birds, especially when the infiltration 

 is present in the ovaries and testes. However, evidence is lacking to indicate 

 that these cells transmit the disease to either mate at copulation. 



The Infiltration of Ovules with Cells Indistinguishable from 

 Neurolymphomatous Cells from Ovarian Tissue 



The ovule embedded in the ovary of the hen appears to be surrounded by a 

 layer of endothelial cells as shown in Figure 6. In some birds neurolympho- 

 matous cells infiltrate this layer and in others they do not. Resistance to 

 neurolymphomatosis may exist in this layer of cells. However, the methods 

 of resistance to disease are so little understood that it is best for the time being 

 to state this as a suggestion rather than as a fact. It was not possible to make 

 a thorough histological study of the ovaries of all the birds in these experiments. 

 But those that were picked at random indicate that neurolymphomatous cells 

 from the coeliac plexus frequently infiltrated the tissue of the ovary and less 

 frequently the ovules embedded in this tissue. This has been known for 

 several years, and Gibbs (1934) stated that "The pathological cell responsible 

 for these malignant growths (neurolymphomatosis) occasionally develops such 

 invasiveness that any or all tissues are affected." The foundation of the 

 present investigation lies in the findings of earlier studies which have never been 

 published in full. 



The results of the histological studies showing infiltration from the ovary to 

 the ovule are reported in Table 15. 



