456 Dr. .J. C. E wart. On Rigor Mortis in Fish, [June 16 y 



Both specimens are still (June 16th) in well marked rigor, and in the 

 muscles near the cut surface I have been unable to detect any bacteria, 

 and the reaction of the muscles is still slightly acid. 



These and other experiments justify the conclusion that rigor, 

 under ordinary circumstances, is in all probability driven away by 

 putrefactive organisms. One of the most remarkable changes which 

 accompanies the disappearance of rigor is the change of reaction of 

 the muscles from acid to alkaline. As soon as the rigor begins to 

 lose its hold the acidity diminishes, and gradually or rapidly dis- 

 appears ; for a time the muscles are neutral, but sooner or later they 

 are distinctly alkaline. The muscles around the body-cavity become 

 alkaline first, from these muscles the alkalinity extends outwards 

 towards the skin, and later extends into the musclesvof the tail, but 

 in some cases a long interval elapses between the appearance of the 

 alkaline reaction in the sub-peritoneal muscles and the myotomes 

 situated behind the body-cavity. A point of considerable interest is 

 that the reaction of the muscles under the skin passes from acid to 

 alkaline before they are invaded by bacteria. This can be readily 

 proved by introducing into a culture-medium a fragment of muscle 

 from under the skin of the trunk from which the rigor has just 

 gone, and which is already faintly alkaline, and as a test experiment 

 a similar fragment from under the peritoneum from a point as nearly 

 as possible opposite where the first was taken. In the latter case 

 bacteria rapidly appear, while no bacteria (if all the necessary condi- 

 tions have been observed) will appear in the former. By a series of 

 experiments I have proved that while weak solutions of hydrochloric 

 and sulphuric acids are incapable of preventing the putrefaction of 

 fish, they have the power of arresting or at least greatly retarding the 

 development of ordinary bacteria. Seeing that the alkaline wave 

 radiates from around the body- cavity in advance of the bacteria, it is 

 extremely likely that the one results from the presence of the other. 

 In fact we may, until further experiments have been made, suppose 

 that rigor disappears in the presence of a species of fermentation, 

 that the bacteria which reach the tissues from the body-cavity manu- 

 facture ferment-like substances, which as they diffuse through the 

 muscles drive the rigor before them, adapting the tissues on the 

 way for the suitable reception and nourishment of a crop of putre- 

 factive bacteria in much the same way as the husbandman breaks up 

 and otherwise prepares the soil before sowing his corn. In all pro- 

 bability the duration of the rigor partly depends on the readiness 

 with which the tissues can be made alkaline, and partly on the 

 amount of mechanical obstruction the bacteria have to overcome in 

 the muscular fibres. It is well known that gelatine and other 

 culture-media, when slightly acid, or when too much dried, are 

 rendered for a time altogether unsuitable for the cultivation of 



