262 
Proceedings of Eoyal Society of Edinburgh. [june 6, 
5. On the Presence of Bacteria in the Lymph, &c., of Living 
Pish and other Vertebrates. By J. C. Ewart, M.D., 
Begins Professor of Natural History, University of 
Edinburgh. 
Baring the last ten years numerous investigations have been 
made to ascertain whether ordinary ( i.e ., non-specific) bacteria exist 
in the tissues of apparently healthy, living animals. As a result of 
these inquiries, it has been clearly shown that while there is no 
evidence of the existence of bacteria, under ordinary circumstances, 
in the blood of the higher Vertebrata, there is abundance of evidence 
of their presence in the blood of some fishes. 
The existence of bacteria in fish has been specially studied by 
MM. Olivier and Bichet. In a communication on the Microbes 
of Marine Pish,* Olivier and Bichet point out that bacteria exist 
(sometimes in great numbers) during life in the peritoneal fluid, 
lymph, and blood of the whiting, red mullet, sand-eel, wrasse, dab, 
and several other fish. Of the fish examined, the authors state that 
(with the exception of the conger and the dog-fish) all the tissues 
contained numerous bacteria, — long and short bacilli being espe- 
cially abundant. By cultivations it was shown that bacteria also 
existed in the tissues of both the conger and dog-fish. From the 
observations made, Olivier and Bichet conclude that bacteria occur 
so constantly in fish that they must be almost considered as 
normal, and, further, that they are not putrefactive bacteria, because 
when they rapidly multiply after the death of their host there is no 
evidence of putrefaction. 
In two subsequent papers (one dated 9th July and the other 17th 
September 1883) the original observations are confirmed, and it is 
further pointed out that bacteria are especially numerous in the 
peritoneal cavity, and less numerous in the pericardial sinus, the 
cerebro-spinal canal, and the blood of the heart, and that under 
certain conditions the bacilli are mobile, and capable of being cul- 
tivated. 
I have recently had the opportunity of examining the blood, &c., 
of a number of both marine and fresh-water fishes, and I am able 
* Compte Rendu , tome xcvi., Fevrier, 1883. 
