NEOPLASTIC DISEASES IN CHICKENS 3 



Cases of tumors have been collected here for a period of several years. This 

 accumulation has now reached a size sufficient to merit collective study and 

 constitutes the basis for this bulletin. This study may be expected to contribute 

 to the knowledge of the morphological characteristics of the various types of 

 neoplasia as well as to provide information on the relative incidence of the specific 

 types. No attempt is made to provide a comprehensive review of the literature 

 since this was adequately done by Heim (12), with reports up to about 1930. 



SOURCE OF MATERIAL AXI> METHODS 



The cases of tumor were derived from three general sources. The principal 

 source was the laboratory of the Poultry Disease Control Service maintained 

 at the Massachusetts State College. Commercial poultry flocks of Massachusetts 

 submit chickens suspected of disease to this laboratory for examination and 

 diagnosis. During a two-year period from December 1, 1937, to December 1, 

 1939, all specimens received by the diagnostic laboratory and suspected of neo- 

 plastic diseases at the time of necrops>- were examined histologically. Those 

 cases found to be neoplastic were included in Collection A. A second source of 

 material was a flock of chickens maintained at the college by the Department of 

 Poultry Husbandry for genetic study. Some of the chickens that became ill or 

 died were submitted for e.xamination, and cases of neoplasia observed between 

 December 1, 1937, and December 1, 1940, were included in Collection B. A 

 third source of material (Collection C) consists of cases of neoplasia collected at 

 random from various sources, such as cases found in birds serving as controls 

 for experimental work and cases studied prior to December 1937 on which ade- 

 quate information was available.^ 



A tentative diagnosis of the neoplasm was made at the time of necropsy ia 

 the majority of cases. These diagnoses were later correlated with the final diag- 

 nosis, which was arrived at with the aid of histological examination. This was 

 done in an effort to determine the accuracy of a diagnosis made as a result of a 

 gross examination only. This phase of the work should be of importance to those 

 doing diagnostic work who have neither the time nor the facilities for histological 

 study o'f material submitted to them for diagnosis. 



Chickens suspected of neoplasia at the time of necropsy were carefully ex- 

 amined and sections of organs involved or suspected of involvement were pre- 

 pared for histological examination. Smears of the blood were prepared when 

 possible from chickens suspected of a blood dyscrasia. The routine procedure 

 for histological e.xamination was to use a hemotoxylin and eosin stain of formalin- 

 fixed material. Special methods were used in some instances when required to 

 establish a diagnosis. 



A stud\' of neoplastic diseases must necessarily have a scheme for naming 

 and classifying the various forms of tumor encountered. In this connection 

 much use was made of the standard books dealing with oncology. The works 

 of Ewing (5), Feldman (7), and Jackson (13), particularly, have been of invaluable 

 assistance in this respect and they, together with the contributions of other in- 

 vestigators mentioned in the text of this article, have served as guides for the 

 stud\' of the tumors encountered in chickens. The scheme of classification 

 adopted is presented in Table 1. In general it follows the commonly used, simple 

 scheme of classifying tumors according to the tissue from which they are derived. 

 In the schematic classification are listed only those varieties of neoplasia which 



^The authors are indebted to Dr. W. A. Hagan, New York State Veterinary College, Ithaca, 

 N. Y., tor permission to use certain material collected while one of them (CO.) was associated 

 with that institution. 



