43 



On the Resting Spores of Protococcus pluvialis. 



By T. Charters White. 



(Read January 23, 1880.) 



In defining the " scientific frontier " between the lowest forms of 

 animal and vegetable life as revealed by the microscope, the student 

 is met by difficulties of no ordinary character — he will meet with 

 organised bodies sometimes simulating animal, at others vegetable 

 life ; but the boundaries will be so interlaced that it will be 

 extremely difficult to draw the line that shall mark the separation 

 of the two kingdoms. 



The subject of my casual communication this evening deals with 

 one of these classes of objects, and one that by an ordinary 

 observer would be undoubtedly placed in the animal world, did not 

 chemical analysis teach him that it was a vegetable — an alga of the 

 simplest type. Possessed of less than ordinary powers of observa- 

 tion, I cannot hope to lay before you any very novel details in 

 reference to my subject, but I may be permitted for a few moments 

 to lay before you sufficient to awaken an interest in the examination 

 of Protococcus pluvialis, some specimens of which I have placed 

 under my microscope on the table. The subject has been well 

 studied by such eminent men as Ehrenberg, Cohn, and others, and 

 it is to their monographs and those of our British Algologists 

 that I would refer you for further and more intimate acquaintance 

 with a subject of much interest to the microscopical observer. 

 Protococcus has been variously named Chlamydococcus, Hcemeto- 

 coccus, &c., but as it is better known as Protococcus, it may be 

 desirable that I should use that name in describing it. 



When first met with, the observer is impressed with the convic- 

 tion that what he is looking at are veritably moving animals. 

 They are seen jDrogressing with a rapidly rotating action, are coloured 

 a pale green, and are furnished with a red eye speck. A closer 

 examination will be needed before their true character is made 

 evident. Many of the old writers, as Ehrenberg, claimed them as 

 Infusoria ; but others , as Cohn, with a juster determination, have 



JouRN. Q. M. C, No. 43. e 



