574! EHRENBERG ON ORGANIC MOLECULES AND ATOMS. 



the body and with sharp outlines. In larger infusoria which are ^ of 

 a line or more in diameter, these internal receptacles are recognised as 

 evident membranaceous sacs, which often make their appearance isolated 

 when the animalcule is pressed or when it divides itself, and which have 

 been supposed to be separate infusoria, internal monads. From this 

 fact of the reception of nutritive substances by the smallest monads, we 

 have no reason to admit any other office for the organs of nutrition. 

 The sharply-outlined coloured points in the interior of the body of mo- 

 nads are to be regarded as small filled membranaceous vesicles or bellies. 

 Now in the larger infusoria of similar structure we can discern, when 

 two such bellies touch one anotlier, that the thickness of the ventral 

 partition is in comparison with the diameter of the belly extremely 

 thin ; that the former is seldom perceptible ; and that the membrane 

 forms around the contents a mere mathematical spherical superficies. 

 Scai'cely any one therefore would suppose a greater proportion than 

 20 to 1 in the smallest. Granting however the thickness of the 

 partition to be only ^^ of the diameter of the belly, this would amount 

 to xeoVoo °^ ^ ^"■'^' ^^ T92O000 ^^ ^" inch, in individuals of Monas 

 Termo QimX) ^^ ^ '"^^ ^" ®^^^' "^ ^^'hich the bellies measure but ^ of the 

 whole length of the body, and are therefore ^ g l^ „ ^ of a line in diameter; 



and since there is reason to look for vessels in these partitions, this 



therefore places the organic atoms at a distance which I must, since 

 they are purely hypothetical, pass over, and leave as a subject of direct 

 subsequent inquiry. 



There are still more powerful reasons for the probability of many 

 much smaller magnitudes. According to my observations mentioned 

 in one of the foregoing pages, there is in the body of the polygastrical 

 infusoria a substance finely granular and reticular, — either in appearance 

 from the impressions of the numerous small bellies, or really so, — which 

 surrounds the Avhole of the intestinal canal and the masticating appa- 

 ratus, and is secreted partly upon the solution of the individual forms, 

 partly by the anal aperture, without any prejudice to the continuation 

 of their being*. This perceptible substance I have taken to be the ova- 

 rium : the granules of this ovarium in Kolpoda CucuUus are to the 

 mother animalcule as 40 to 1, others as 80 to 1 ; and they appear to 

 c^row finer with the decreasing size of the body, being no longer of 

 themselves visible. Now it is probable that only the'r transparency and 

 the weak power of the microscope hinder us from finding such an 

 ovarium in the monads in every other respect so similar. We must not 

 however overlook that there may be young monads still inclosed in the 

 egg' o"" J"**^ ^°"*^ ""^ ^''*^™ ^*' *^^ diameter of the ^^ hole length of whose 

 body Mould be but the y ^^^^ to jhttoo of a line ; these may have 

 bellies which tliei , in like propoilion, would be in diameter ^ooo^ ^^ 

 ' See supra, p. 563. 



