566 NIACIN 



tongue. Goldberger et al.^ studied a case of naturally occurring blacktongue 

 and later described a similar disease in dogs wliich was produced experi- 

 mentally.^ Dogs suffering from this deficiency show very characteristic 

 findings. The first abnormality is, usually, refusal to eat. The animals are 

 quiet and apathetic. After a day or two the inner surfaces of the lips, 

 cheeks, and gums become diffusely inflamed and develop superficial yellow- 

 ish necrotic patches. There is an intensely foul odor. Excessive drooling of 

 thick ropy saliva is characteristic. The tip and margins of the tongue be- 

 come red and later develop dark bluish patches. Ulceration frequently 

 appears on or under the tongue. A diarrhea, generally bloody, is present. 

 Scrotal dermatitis may be found. Vomiting usually develops. Body tem- 

 perature may reach 40 or 41°. At autopsy, the tongue is found generally 

 to have assumed a deep bluish-black color. The inflammatory changes in 

 the mouth may extend to affect the epiglottis, the soft palate, and even 

 into the esophagus. The stomach may show small areas of congestion, 

 although during life it is apparently normal to endoscopic examination.^ 

 Small and large intestine, and particularly the rectum usually show patches 

 of intense congestion, less commonly small hemorrhages. Duodenal or 

 colonic ulcers may be found. 



Denton** studied the pathological changes in Goldberger's dogs. He found 

 degenerative lesions in the mucous membranes of the mouth, pharynx, 

 esophagus, intestines, and epithelium of the scrotum. The lesions seemed 

 to originate in the supporting tissues of the membranes and terminated in 

 extensive necrotic and diphtheritic inflammation. Lillie^ made a detailed 

 histologic study of the tissues of blacktongue dogs. In addition to pre- 

 viously described findings, he noted degenerative changes in the nerves 

 regional to the oral lesions, granular degeneration of heart muscle fibers, 

 moderate passive congestion, and relatively little fatty infiltration of the 

 liver. The spleen was fibrotic and contained atrophic follicles. Albuminous 

 degeneration of the epithelium of the convoluted tubules of the kidney, 

 injection of the meninges, tigrolysis of the brain stem ganglia, nerve cell 

 atrophy, and pericellular vacuolation in the cortex and basal ganglia were 

 found. Jensenius and Norgaard^ also found extensive histological changes 

 in the central nervous system, particularly the spinal cord. 



The fatty livers (yellow liver) sometimes seen in dogs on blacktongue- 



3 J. Goldberger, W. F. Tanner, and E. B. Saye, Public Health Repts. {U. S.) 38, 

 2711 (1923). 



4 J. Goldberger and G. A. Wheeler, Public Health Repts. (U.S.) 43, 172 (1928). 

 ^ J. A. Layne and J. B. Carey, Gastroenterology 2, 133 (1944). 



« J. Denton, Am. J. Pathol. 4, 341 (1928). 



7 R. D. Lillie, Natl. Insts. Health Bull. 162, 13 (1933). 



* H. Jensenius and F. Norgaard, Acta Pathol. Microbiol. Scand. 19, 433 (1942). 



