On High-Power Definition. 



177 



Whilst awaiting Professor HuizLnga's fuller account of his experi- 

 ments, we may point out that the hypothesis of an inhibitory influ- 

 ence of increased density should be supported by experimental 

 evidence, and that it cannot apply to tubes closed before boiling. 

 The neck of the flask closed with asphalt may (so far as condi- 

 tions are stated by him at present) harbour Bacteria, as in our 

 Series F. But especially we would urge upon him and others that 

 it is undesirable, as yet, to introduce into the discussion other 

 organic mixtures. Turnips and cheese may be very bad material 

 for experiment ; but it would be well, as far as possible, to settle 

 the matter, or the way in which the matter is to be viewed with 

 regard to them, before going off to other particular cases. 



It would be a very excellent thing if all further reference to 

 this subject could be postponed for a year or two — that is, until 

 further study of Bacteria, such as that inaugurated by Sanderson 

 and Cohn, has given us surer ground to tread upon, 



" Note on High-Power Definition as illustrated by a compressed 

 Po(iw/-rt-scale." By E. B. Beaumont, P.E.S., and Dr. Rotston- 

 PiGOTT, F.E.S. 



Nothing in microscopic matters has ever afforded us such com- 

 plete satisfaction as the following result of a very fine defini- 

 tion, accomplished by means of a Gundlach German -Jg- immer- 

 sion lens, corrected by a new method, which Dr. Pigott at present 

 delays publishing in the hope of further improvement, but which 

 he is willing to exhibit at his house. 



A PocZwra-slide *, fortunately strongly protected \vith a thick 



Podura-^coXe. 



glass cover, ha\ing accidentally been subjected to so considerable 

 a pressure as to crush out the structure of a large scale, upon 

 bringing it, by haphazard, into the field of view with a magnifnng- 

 power of about 2000 diameters, exhibited a structure indicated by 



Podura Degeeria vol domettica. 



