326 MICRO-ORGANISMS AND DISEASE [cHAP. 



the congested portions, the lung was seen to be highly 

 cedematous, a large quantity of blood-tinged serum flowing 

 from and accumulating at the cut end; the lobules were 

 well mapped out, and there was also sharp demarcation by 

 cedematous connective tissue between the normal lung 

 tissue and the deeply congested lobules, as also between 

 groups of lobules and individual lobules in the congested 

 areas ; haemorrhage appeared as spots and patches on the 

 parietal and visceral pericardium. The liver showed yellow- 

 grey necrotic patches, the spleen showed grey, necrotic 

 streaks in the capsule ; both kidneys showed congestion of 

 the medulla, and fatty patches in the cortex. We have, 

 then, in both these animals a striking result, completely 

 coinciding with the disease in the cat. 



The next important point ascertained in these cows had 

 reference to the distribution of the diphtheria bacilli inocu- 

 lated. In the tissue of the tumour in both animals aftei" 

 death, i.e. after fourteen and twenty-four days respectively, 

 the diphtheria bacilli could be demonstrated without any 

 difificulty under the microscope in the sections and by 

 culture. On sections the necrotic tissue of the tumour 

 contained great numbers of the bacilli in clumps ; culture 

 experiments on gelatine and on Agar with a particle of the 

 tissue of the firm tumour produced innumerable colonies of 

 the diphtheria bacillus ; when examined under the microscope 

 they resembled the human diphtheria bacillus in all respects. 

 They were also tested on guinea-pigs and found to act 

 extremely ■ virulently, causing death of the animals under 

 the typical 'appearances in thirty to fifty hours. But neither 

 in the heart's blood nor in the lung or liver of these cows 

 could any microbes be demonstrated in microscopic speci- 

 mens or by culture. So far, then, there is complete analogy 

 between the cows, guinea-pigs, and cats, that is to say the 



