184 Transmutation of Form in certain Protozoa. 



their patients with the statement that " there are some small cavities 

 in the teeth which can be left without disadvantage until another 

 time." It also shows most clearly the necessity of following up 

 the fissures, which generally extend from a central cavity of decay 

 in the grinding surfaces of molars; careless operators contenting 

 themselves with only removing the caries from the central cavity, 

 leave these fissures untouched, and, as a consequence, decay pro- 

 gresses unobstructed and unnoticed, until the tooth is rendered a 

 mere shell. 



V. — Transmutation of Form in certain Protozoa. 



By Metcalfe Johnson, M.R.C.S.E,, Lancaster. 



Plate C. 



Part II. 



On Thursday, August 3rd, 1871, Professor Huxley congratulated 

 the British Association at Edinburgh on the fact that two gentle- 

 men of high attainments. Prof. Thompson and Sir William Thomp- 

 son, had declared themselves in favour of the doctrine of evolution. 

 It cannot therefore be less a matter of satisfaction to the humbler 

 labourers in this department (the working bees in the hive), that 

 such eminent minds give their sujDport to doctrines which it is the 

 object of their (the working bees) comparatively insignificant re- 

 searches to establish. 



While the savans are attending the great annual scientific car- 

 nival, held this year in " Auld Eeekie," I shall content myself with 

 sitting at home and writing to the ' Monthly Microscopical Journal ' 

 on this (to me) important subject of thought and inquiry. 



I had proposed to myself, in this next report to the Journal, to 

 trace the origin of some of the more important members of the 

 group of Infusoria to the simple elements known as Monas and its 

 congeners, but owing to the kind sympathy of Mr. Gr. F. Chantrell, 

 of St. James's Mount, Liverpool, I am induced to devote this paper 

 to the tracing in greater detail the bearing of Paramoecium to Calli- 

 dina and its allies, the Philodiucea, trusting to reserve the other sub- 

 ject to a future communication. 



In a recent letter, Mr. Chantrell writes as follows : — " I have 

 thought a good deal of your papers, and am particularly interested • 

 in your subject. I think (on) the first meeting of our private 

 Microscopical Society (the Liverpool Natural History and Micro- 

 scopical Society) after your last paper appeared, I exhibited a Car- 

 chesium 'polyjpinum, in which the evening before I had noticed some 

 of the Vorticella heads had disappeared, and in their place, amongst 

 the branches, I noticed a globular-shaped substance. On this 

 evening, to my amazement; all the Vorticella heads were gone, and 



