Mettam — Malignant Tumours in Birds. 69 



round this cell-inclusion, and now the opinion is held that the body is not an 

 animal parasite, but a cell-degeneration, or a secretion of the cell, or the 

 persisting archoplasm with centrosomes. Some maintain that the new 

 growths are due to blastomycetes; and certain it is that in some tumours 

 blastomycetes or yeast-like organisms can be found. Others, again, maintain 

 that the tumour-growth follows some change in a body-cell which causes it 

 to get rid of some of its chromatin from the nucleus, the cell then behaving 

 like the germinal epithelium of testis and ovary, capable of unlimited 

 proliferation. There appears to be little doubt but that the cell-mitoses are 

 in many cases heterotypical ; but it seems that here we have the effect of some 

 unknown cause operating, and that we have not the fundamental change which 

 produces the effect. Eecently Borrel found acari in the infective sarcomata 

 of dogs, and asks if there is any relation between the acari and the genesis of 

 the tumour. I have cut many specimens of infective sarcomata, and never seen 

 an acarus ; nor am I aware that anyone else has met with them. They are 

 probably accidental, as may be the spirochsetes which I found in tumours that 

 came into my possession. 



From this brief resume of some of the opinions held as to the cause of 

 new growths, it will be observed that we are far from agreeing as to the cause ; 

 but we are likely to get nearer the truth as to the etiology of malignant 

 neoplasms if we examine the tumours found in animals throughout the animal 

 kingdom. It is with this object that I desire to describe certain malignant 

 new growths that I have recently met with in birds. Tumours are not 

 unknown in birds. Non-malignant tumours, as fibromata and myxomata, are 

 not uncommon. Birds suffer from epithelioma contagiosum — an epithelial 

 new growth, possibly produced by an ultra- microscopic germ, because, if an 

 emulsion of the tumour be made and passed through a porcelain filter, the 

 filtrate contains the virus, and on inoculation will set up the disease. Other 

 new growths, tumour-like, have been shown to be due to organisms, the 

 tubercle bacilli, for instance. Birds do, then, suffer from neoplasms — true 

 new growths of undetermined cause ; but, with the exception of epithelioma 

 contagiosum, descriptions of such are wanting. 



Eecently Pick has described squamous epithelioma in a bird's tongue. 



The specimens I have met with are examples of sarcomata, the tumours 

 in both instances having become generalized, and a carcinoma. 



Tlie Sarcomata. Case 1. — Pure-bred Plymouth Eock-hen, apparently 

 about two years old. The fowl was very thin and emaciated. On removing 

 the feathers numerous swellings, new growths, were found. None of them 

 was ulcerating, and all appeared to be firmly attached to the subjacent 

 structures, the skin moving easily over them. The new growths were 



R. I. A, PROC, VOL. XXVII., SECT. 5. [If] 



