Mr.W. Addison on the Sacculi of the Polygastrica. 101 



124. Pitta brachyura. I purchased a living specimen of a dealer, 

 which was probably procured at no great distance. 



125. Oriolus Hodsonii {Hodgsonii}), Swainson ; O . melanocephalus 

 of India, as distinguished from that of Africa, auctorum. Very com- 

 mon throughout the year. 



126. 0. galbula. I obtained a living specimen of this European 

 species, which I kept for several months in confinement. Its ordi- 

 nary Indian representative, 0. aureus (common in the peninsula), I 

 have not yet seen from this part. 



[To be continued.] 



XIII. — On the Sacculi of the Polygastrica. By W. Addison, Esq. 

 To the Editors of the Annals of Natural History. 



Gentlemen, 

 As Dr. Griffith, in his paper '*^0n the Sacculi of the Polygastrica*,^* 

 has coupled my name with a very inaccurate interpretation of the 

 effect of the liquor potassce on the Paramecium, allow me to abs- 

 tract from my *^ Experimental Researches^ all that I have pub- 

 lished on the subject. 



" I had often remarked the very great similitude of size and 

 appearance between several of the smaller forms of the Poly- 

 gastric animalcules and some of the varieties of pus-corpuscles ; 

 so great is this similarity, that in many instances it would have 

 been difficult to distinguish the one from the other, had it not 

 been for the voluntary and very active movement of the animal- 

 cules. Now liquor potassce produces upon these animalcules the 

 same effect as it does on the colourless blood- and pus-corpuscles ; 

 it penetrates the transparent integument of the animalcule by 

 imbibition, and causes it to burst open and discharge its con- 

 tents, which have the same appearance as the molecules and gra- 

 nules from the colourless blood- and pus-corpuscles. 



" In the larger forms of the polygastric animalcules there are 

 a great number of large vesicles or cells (which have been called 

 stomachs) very visible in their interior ; and these are all dis- 

 charged from the bodies of the creatures in the same way, when 

 they are submitted to the action of liquor potassce. These so-called 

 stomachs may be seen enlarging in the interior of the animalcule 

 prior to the rupture of the external integument ; and when they 

 are discharged from the body of the animalcule, numerous mi- 

 nute molecules may be seen within themf/^ In the former of these 

 paragraphs it is evident that I am speaking of animalcules ten or 

 twenty times less than the Paramcecium ; and in the latter, when 



* In the June Number, p. 438. 



t Experimental Researches on Inflammation, and on the origin and na- 

 ture of Tubercles of the Lungs. Churchill, 1843. 



