OBSEUVATIONS ON FII.ARI^. G5 



First — The rapidity of tlie current is diminished in the recum- 

 bent posture, and (m luomen and children at least) still further 

 during sleep. It seems probable that there may also be an integral 

 change in the relation of the red and white corpuscles approaching 

 that which takes place when the circulation is retarded in the web 

 of a frog's foot. This modification of the internal current of the 

 main current may cause the Filariw to adhere to the sides of the 

 vessels during raj^id circulations, and to fall into the stream when 

 it moves more slowly. 



Second — The oxygenation of the blood at night and in repose 

 is suj^posed to be less complete than during the day ; although 

 some experiments made by Pettenkofer and Voit point to an oppo- 

 site conclusion, and make it ajDpear that of the total amount of 

 oxygen taken in during twenty-four hours 67 per cent, is taken in 

 by night, and only 33 per cent, by day ; 58 per cent, of the 

 carbonic acid eliminated during twenty-four hours being given off 

 in the day, and 42 per cent, by night. From these results Somner 

 drew the inference that sleep was caused by exhaustion of the 

 reserves of oxygen during the waking state, that oxygen was 

 stored during sleep, and that when the equilibrium was re-established 

 by accumulation the subject awoke. This hypothesis is barely 

 tenable, but it is worth while to mention it in this connection 

 because it accords with the presumption that the blood is more or 

 less abundantly charged with oxygen during sleep ; and this may 

 help to determine the location of the Filarice. 



Third — The temperature of the blood is probably lower (or it 

 may be higher) relatively to that of the tissues during sleep than in 

 the alteration of state consequent on the presence, or absence, of 

 special elements derived from the food. It does not seem likely 

 that there can be any considerable change of condition consequent 

 upon tie periodic or occasional discharge of lymph and chyle into 

 the blood ; but it may happen that when the circulation is slow and 

 the body lies recumbent, the parasites are thrown into the main 

 current and therefore appear in greater numbers. 



Jt is premature to speculate on the causes of a phenomenon which 

 may yet prove to be exceptional ; but if the conclusion arrived at 

 should be maintained, it will certainly be the duty of physiologists 

 to pursue further into detail than they have e\er yet been carried 

 certain neglected inquiries as to the altered conditions of the blood 

 during sleep, and when the brain and body are awake. 



