the Distinctive Characters in Amoeba. 121 



again, observed the nucleus with its hyaline ring, the action of 

 the contractile vesicle, granules, and the villous tuft in specimens 

 of J. villosa not exceeding ^ ^'3 pth of an inch in length, and 

 ■ 1 o^op th of an inch in breadth, the lens employed being a ^th 

 with an A eye-piece. I candidly confess, therefore, that it would 

 have spared me no little pain had Mr. Carter abstained from 

 making an observation so uncalled for, and at the same time so 

 much at variance with his own experience. 



In answer to Mr. Carter's statement respecting the impossi- 

 bility of distinguishing the characters of an Amoeba until it has 

 attained the length of i-J-oth of an inch, it may suffice to men- 

 tion that, out of the twenty-five so-called species of the genus, 

 six are generally described as being under 4-3-0^^^ 0^ ^^ iiich in 

 length, even when full-grown; whilst a refutation of the view 

 regarding the nucleus of such specimens will be found in some 

 important observations (by Dr. W. Roberts of Manchester) on 

 the minute structure of the human and other " blood-corpuscles," 

 which appeared in the same Number of the 'Annals' (p. 60 

 of the present volume) as Mr. Carter's remarks on Amoeba 

 princeps. 



But, irrespectively of the observations of others, those pre- 

 viously published by Mr. Carter himself contain abundant evi- 

 dence that he has not always held the same opinion on this 

 point ; and it is only necessary to adduce one, out of several that 

 might be brought forward, to show that the limits now assigned 

 to the successful employment of the microscope have been con- 

 siderably exceeded by him. Thus in his paper on the Infusoria 

 of Bombay, published in the 'Annals' for 1856, we find a de- 

 scription and figures oi Euglypha alveolata, exhibiting "ovules" 

 with their capsules, both within and without the test — the nuclei 

 of these clearly defined when ^poVo^h of an inch in diameter, an 

 equally detailed representation being afforded of " the separation 

 and development of granules into spermatozoids (?) within the 

 test " — and, in one example (namely. Astasia limpida), a clearly 

 defined view of the discoid ovules only g-gVo^h of an inch in 

 diameter, but nevertheless "showing its capsuled character;" 

 whilst in the 'Annals ' for the succeeding year (vol. xx. p. 33), 

 it is stated that certain bodies, ^ ■j\ 5 th of an inch in diameter, 

 "are polymorphic, and present the granule and contracting 

 vesicles like the monociliated sponge-cell of the ampullaceous 

 sac" [of Spongilla'], and that "they also enclose particles of 

 food." A figure is given of these bodies. Here, then, at all 

 events, we have an Amoeboid organism, with some of the very 

 characters present which Mr. Carter has recently declared it to 

 be impossible to trace with accuracy, — the smallest of my 

 Amcebce, as referred to, having been -oVo^h of an inch in length. 



