No abstract

The preceding paper contains the results of various reinoculation experiments in which the viruses of rabbit pox, virus I I I disease, infectious m y x o m a of rabbits, culture (dermo) vaccinia, and neurovaccinia were compared (1). The findings with respect to the reaction of recovered rabbits to exposure to clinical cases of pox, together with the observations on a calf inoculated with pox, two specimens of vaccine virus, and neurovaccine were also reported. The present paper is concerned with the results of the serum neutralization tests in which various combinations of the viruses and the immune sera of pox, vaccinia, neurovaccinia, and virus I I I were studied. Materials and MethodsThe various virus emulsions were prepared from tissues obtained from cases of acute orchitis produced by intratesticular injection of tissue-virus. The testicles were ground with alundum and Locke's solution to make a suspension of 10 to 20 per cent concentration by weight. Gross particles were removed by low speed centrifugation. The emulsions were kept in the ice box while their bacterial sterility was tested.The immune sera were obtained from rabbits inoculated 17 to 134 days previously or in the case of spontaneous pox, a fortnight or more after all signs of the disease had healed. Each specimen was kept in sealed tubes in the ice box. The sterility of each serum was tested before tubing and before use.The tests were carried out in the usual manner. Desired dilutions of virus or serum were made with Locke's solution. Equal parts of tissue-virus emulsion and of serum were thoroughly mixed in small sterile Petri dishes and allowed to stand at room temperature 1½ to 2½ hours; 0.2 cc. of the mixture was then injected 379 on

Previous reports from this laboratory on the hemacytological constitution of the rabbit have been limited to observations on male animals. These studies have now been extended to normal females and to females presenting various defects referable to constitutional (hereditary) or environmental influences. It is the purpose of the present paper to present one aspect of these studies; namely, a comparison of the blood cytology of normal male and female litter mates. These comparisons were made in order to determine whether there were statistically significant differences between values obtained for any of the blood cells of the two sexes. Furthermore, correlation coefficients were calculated with the purpose of disclosing to what extent a knowledge of the blood cytology of a buck was relevant information concerning the blood cytology of a litter mate sister. Material and MethodsObservations were made on the blood cytology of 41 pairs of normal rabbits, each pair consisting of a buck and a doe of the same litter; an analysis of these observations forms the basis of the present report.Animal Materiat.--All animals were bred and raised in this laboratory, and all were bred in pure line from standard stock with the exception of three pairs of Rexes. These were obtained by a back-cross mating of an F1 Rex to a pure line Rex parent and were of normal Rex type. The breeds and the number of animals in each breed were as follows: Havana 7; Dutch and Rex 6; Himalayan and Beveren 4; English, Chinchilla, and Belgian 3; Polish and Silver 2; Tan 1. All the rabbits were virgin stock and gave no evidence of disease as determined by careful clinical examination. The age ranged from a minimum of 16.0 weeks to a maximum of 37.8 weeks, with a mean value of 26.0 4-0.59 weeks.Housing and Feeding.--The buck and doe comprising a pair were weaned at

Within the period of 2{ years, the rabbit breeding colony maintained at the Institute for studies on constitution has been the locus of three separate epidemics of a disease, which because of its similarity to small pox in man, has been called rabbit pox. The first epidemic occurred in the spring of 1930 and was limited to a small colony of animals housed in a single room. The disease was characteristically mild with low morbidity and mortality rates. As soon as its contagious nature was recognized, animals presenting the clinical features were segregated or sacrificed, with the resulting abatement and disappearance of the disease in epidemic form. A few transmission experiments were attempted but without definite success. This outbreak was not studied systematically, but aerobic and anaerobic cultures of blood and tissues from animals with active lesions and animals that died of the disease were negative.The colony was thereafter maintained under vigilant scrutiny for the first evidence of a recurrence of the affection, but no case was detected until the latter part of 1932, when the disease again appeared, this time with explosive violence and in a highly malignant form. The clinical, pathological and epidemiological aspects of this second epidemic have been the subjects of reports by Greene (1-5). Transmission experiments conducted by Pearce, Rosahn and Hu (6) were successful, and the etiological agent was identified through clinical, pathological, immunological and host-range experiments as a filterable virus, qualitatively related to vaccine virus, but more virulent.With the subsidence of the second epidemic approximately 2 months 331

The clinical manifestations and course of disease observed in experimental rabbit pox have been described and analyzed. The condition differed from the acute fulminating and rapidly fatal type of experimental infection (1) in that the period of survival was longer, a variety of clinical manifestations developed and a considerable proportion of the cases recovered. The most conspicuous symptom was a generalized papular eruption on the skin and mucocutaneous borders. The production of the disease was associated with routes of inoculation other than the intratesticular or with a small dosage. The majority of cases were inoculated with Berkefeld V filtrates of tissue-virus emulsions and not with the more potent unfiltered emulsions. The local reactions resulting from various routes of inoculation were described. Of special interest were the pronounced cutaneous reactions induced by intradermal injection, the high instance of marked clinical manifestations after intravenous inoculation, the failure of lesions to localize in the lines of scarification of skin and cornea even in cases with a profuse cutaneous eruption, and the development of cytoplasmic inclusion bodies in the epithelial cells of the cornea following scarification and conjunctival instillation of virus. In the character of its clinical manifestations and course of disease, experimental rabbit pox was indistinguishable from cases of the spontaneous pox.