TflE NEMATOID H.^LMATOZOA OF MAN. 251 



either belonged to a more advanced stage of the one under con- 

 sideration, the result of a previous ingestion of filarious blood, or 

 belonged to a totally different kind. There is always, therefore, 

 a risk of confusing different parasites in the same insect. Re- 

 peated examinations at the same periods tend, however, to 

 minimise this source of error. During the first twenty-four 

 hours no marked change takes place in the form of the organisms. 



On the second day, however, it will probably be seen that the 

 blood has, to a considerable extent, undergone digestion, and 

 the stomach will no longer manifest the distended condition of 

 the first day. Probably a few altered hsematozoa will be observed 

 in it moving very languidly, presenting the appearance of partially 

 disintegrated fungal filaments when the movements are not mani- 

 fested. Some of them may be actually dead ; these will be 

 found to be stained by eosin solution very readily. 



Between the second and the third day further changes occur, 

 but in order to be able to follow these it will be necessary to 

 examine the other tissues of the insect, as possibly the stomach 

 may contain none; it will, however, probably be found that 

 some of them have migrated into the tissues immediately out- 

 side this viscus. It will now be observed that some of the 

 parasites have become considerably thicker (fig. 7) ; and occa- 

 sionally specimens will be seen with the tail presenting the 

 appearance of a lash (fig. 9) ; the movements are still very 

 sluggish. 



About the fourth day it is probable that examples in various 

 stages of growth will be visible, rendering it extremely difficult 

 or impossible to state precisely what it is that actually does take 

 place ; at least hitherto I have not been able to satisfy myself. 

 About this period, however, I have sometimes seen bodies, 

 apparently composed of precisely the same material as figs. 0, 7, 

 9, undergoing something so very hke cleavage (fig. 8) that J 

 hesitate to state that this act is not one of the stages in the 

 development of the filaria. The figure given (No. 8) is very 

 carefully sketched, and, like all the others, accurately to scale. It 

 will be noticed that one end is partially hidden by some granular 

 matter. This I was not able to press away from the preparation. 

 Other preparations of a like kind were also more or less hidden 

 by granular matter, and in some cases (unassociated, however, 

 with any indications of fission) the parasite appeared to be 

 covered with an encrustation. With regard to the process of 

 division suggested by the appearance of No. 8 I can offer no 

 opinion ; it is quite possible that it forms a part of the develop- 

 mental changes undergone by some other parasite, — such, for 

 instance, as a gregarine. About the fourth day there will also 

 be seen short, thick bodies (very appropriately described by Dr. 



