80 Proceedings of the Royal Irish Academy. 



Lastly, Borrer observed in sections of a tumour of a similar nature to that 

 we have seen, larvae of acari in comparative abundance, and believes that 

 they may be inoculated at coition. He states that experiments are being 

 carried out with the object of determining if they had any causal connexion 

 with the development of the tumour. He also refers to the presence of these 

 animal parasites in his exceedingly valuable resume on Cancer published in 

 the Bulletin de I'lnstitut Pasteur, tome v., 1907. Wade," the latest contributor 

 to the literature of the subject of infective sarcoma of the dog, says that " the 

 growth of the tumour is associated with the development of a toxin which can 

 be isolated from it by filtration, and produces interstitial nephritis, a lesion, 

 as already remarked, associated with the development of the tumour." Wade, 

 however, states in his final conclusions that the nature of the virus cannot 

 be detected, and («) cannot be revealed by any method of staining ; (&) does 

 not pass through a Berkefeld filter ; (c) is probably not an ultra-microscopical 

 micro-organism ; (d) cannot be isolated apart from the tumour ; (e) is not a 

 s])%Tocli(Et&. In the body of his paper he mentions that films made from the 

 tumours were also examined for the presence of spirochsetes as possible 

 etiological factors, but none were found. 



I do not claim any causal connexion between the spirocheete and the 

 tumour; but I have found the parasite present in at least three cases 

 examined, and I have further found that to reveal the parasites it is absolutely 

 necessary to make the films with the least possible delay after removal of 

 material from the patient. The spirochsetes tend to rapidly disappear from 

 material in which they are present. The first time I observed the organisms 

 I went back to the material some hours afterwards to make more films, and 

 found, on examination of the films prepared, fixed, and stained in absolutely 

 the same manner as those obtained immediately after removal of the growth, 

 that no spirochsetes were demonstrable. This observation, which I consider 

 of importance, may explain how it is that the organisms have not previously 

 been observed, though I must also confess that it is not possible in every case, 

 even when the material is obtained under the most suitable conditions, to 

 demonstrate the presence of the organisms. Still, however, the organisms are 

 present in the tumour in certain cases ; and such being the case, and our 

 present knowledge of the causation of tumours being in a nebulous condition, 

 I have" thought it my duty to relate to the Academy my observations. . 



lABorrel: " Lympho-sarcoma du Chien," Comptes Rendus, Hebdomadaire des Seances de 

 I'Academie des Sciences, No. 6, February 11, 1907. 



-Henry Wade: "Infective Sarcoma of the Dog." Journal of Pathology and Bacteriology, 

 vol. xii., January, 1908. 



