394 Miscellaneous. 



Observations on the Structure of Amoeba and Actinophrys. 



At a recent meeting of the Boston (U. S.) Society of Natural 

 History, Dr. J. Wyman gave an account of some observations which 

 he had recently made on an Amoeba. 



The species referred to appeared in some fibrine which had been 

 confined between two plates of glass for the purpose of watching the 

 progress of its decomposition in water. The Amceboe were first no- 

 ticed as minute points, and gradually grew to full size, without any 

 obvious change of form or structure. As seen under the microscope, 

 they appeared to be made up of a spherical sarcodic mass, which was 

 structureless, and in which were imbedded numerous granules, from 

 which last, however, a portion of the circumference of the organism 

 was wholly free. Solid bodies, lodged in the interior, were seen to 

 be discharged at various points in the circumference, seeming to meet 

 with little or no obstruction ; and yet no opening was discovered at 

 any point. When the body to be discharged came near the surface, 

 the sarcode was pushed out before it, becoming more and more pro- 

 minent outwards, and at length broke like a bubble, leaving the 

 contained body free. 



The Amoeba, in one instance, underwent complete spontaneous di- 

 vision in five minutes ; first taking on the shape of a dumb-bell, then 

 the two principal masses receded from each other, the band which 

 united them became thinner, and finally broke, just as does the 

 thread which connects two viscid bodies when drawn apart, and two 

 complete Amoebce were formed. In another instance, the division 

 had become nearly comj)lete, as just described ; but the two masses, 

 instead of separating wholly, again approached each other, and nearly 

 recovered their original shape. 



From the manner in which solid particles pass through these 

 structures, and the rapidity with which the whole organism becomes 

 subdivided, it is reasonable to infer that they have no proper integu- 

 ujent, especially as the microscope fails to reveal such a structure. 



Prof. Henry James Clark said that Actinophrys was particularly 

 interesting, as manifesting a step higher than the simple homomor- 

 phous organization oi Amceba as described by Prof. Wyman. Prof. 

 Clark referred to Kolliker's observations in 1849, as recorded in the 

 'Zeitschrift fiir wissenschaftliche Zoologie,' and showed that, even 

 supposing Kolliker to be correct, the division of the mass of the body 

 into an exterior and interior portion, the former containing much 

 larger vacuoles than the latter, indicated a heteromorphous organiza- 

 tion, tending towards specialization of parts. He also added that 

 he could not agree with Kolliker that Actinophrys is a homomorphous 

 mass with vacuoles, but that he was convinced that the so-called va- 

 cuoles of the outer and inner layers are true cells, with a distinct 

 wall about them, a wall that could be easily recognized with the help 

 of the better sort of microscope-objectives of the present day. Owing 

 to the exceeding transparency of the organism, no ordinary objective 

 will show the walls ; but with a one-quarter-inch lens, of one 

 hundred and fifty degrees angular aperture, made for him, last June, 

 by Tolles, of Canastota, N. Y., he had no diflficulty in working, with 



