1890.J A Contribution to the Etiology of Diphtheria. 77 



interspersed here and there in the threads, could be easily ascertained. 

 In the large number of cultivations that were made of the fresh 

 tumour in both cows, the colonies obtained were all of one and the 

 same kind, viz., those of the diphtheria bacillus ; no contamination 

 was present in any of the cultivations. 



Appendix. May 20. 



Since the above was sent in, the following instructive observations 

 were made with regard to diphtheria in the cat and cow : 



At the beginning of the month of April two cats died at the Brown 

 Institution which had been ill for several days previously. Their ill- 

 ness bore a remarkable similarity with the illness mentioned in the 

 preceding pages as the natural (diphtheritic) disease of the cat, the 

 most prominent symptom being an acute catarrhal affection of the 

 respiratory tract; the animals became much emaciated and died. 

 These two cats which I will call Nos. 1 and 2 had been quite well 

 previously and were kept in cages in a special shed, in which normal 

 cats are generally kept and used for laboratory purposes. Now, after 

 the above two cats, all cats which were put into this shed became 

 affected in the same way : running of nose and eye, injected conjunc- 

 tiva with muco-purulent discharge from the eye : coughing and more 

 or less severe bronchial catarrh ; the animals were quiet and did 

 not feed. Between the beginning of April and the beginning of May 

 fourteen cats became so affected, some more intensely than others ; of 

 these several apparently recovered after an illness of about one week 

 to a fortnight, while five became greatly emaciated, very weak, and 

 the lung trouble having greatly increased, they died, the illness 

 lasting two to three weeks. In all five animals the lungs showed 

 distinct signs of lobular pneumonia. In one cat (which I will call 

 No. 3) there was present in the lower part of the larynx and the 

 upper part of the trachea a whitish false membrane indistinguish- 

 able from human diphtheria membrane ; sections through these parts 

 conclusively prove this. In a second cat (No. 4) the trachea and 

 bronchi contained a thick layer of fibrinous and purulent matter ; in 

 the other three animals the bronchi and infundibula contained puru- 

 lent tibrinous exudation, but the trachea did not show any naked-eye 

 change. In all five animals both kidneys were found conspicuously 

 enlarged and white, the entire cortex being in a state of fatty de- 

 generation. It is clear from this that the disease in these animals 

 was the same disease as was mentioned above as the natural as well 

 as the artificially induced diphtheria. Further confirmation was 

 obtained by microscopic examination of the diphtheritic larynx and 

 trachea of cat 3. On sections made through the affected portion of 

 the larynx and trachea the entire mucous membrane was found con- 



