
302 THE EVOLUTION OF LIFE 
Rodet and Roux say,! “The organisms described 
under the names bacillus coli communis and the 
bacillus of Eberth belong to the same pathogenic 
species, of which they form two varieties removed 
one from the other when they present their classical 
characters, but related the one to the other by a 
series of intermediate forms.” Dr McWeeney, the 
bacteriologist of the Local Government Board in 
Ireland, has also said,2 ‘‘He did not believe that 
there was an essential distinction between the 
typhoid Bacillus, and the Bacillus coli communis” 
which is habitually to be found in the intestine. 
These bacteriologists: agree, therefore, with Leh- 
mann and Neumann, who say such a transformation 
“can scarcely be contested any more.” Under 
what particular set of conditions the one form passes 
over into the other is at present unknown—though 
there is much very strong evidence, as many be- 
lieve, tending to show that typhoid fever occasionally 
arises de novo. It occurs, that is, in isolated cases, 
under conditions in which it is almost impossible to 
believe that contagion can have been operative. 
An epidemic of Diphtheria recently occurred on 
Dartmoor, in the neighbourhood of Princetown, 
which was carefully investigated by Dr Deene 
Sweeting of the Local Government Board. His 
report is valuable from the light that it throws 
on the de novo origin of this contagious disease— 
especially as previous reports concerning other 
epidemics of the same malady by skilled investi 
1 Lyon Médicale, 1891, xviii. p. 325. 
2 Lancet, 1896, i. p. 995. 
