276 



HARDWICKE'S SCIENCE-GOSSIP. 



•with blunt and slightly bent, sometimes abruptly 

 attenuated, and crooked ends, translucent, 33-4^ m 

 thick ; forming thin white layers. 

 In marshes and on wood underwater. (Fig. 215, d.) 



48. B. minima. Warm. 



Very minute, actively motile and flexile. The 

 longest specimens about 40 [x. long, i • 8-2 yu thick ; 

 articulations discernible in the form of delicate trans- 

 verse bars. Each joint about half as long as broad. 

 Without granules. 



In sea-water. 



IX. Cladothrix, Cohn. Threads like those of 

 Leptothrix, very slender, colourless, not articulated, 

 straight or slightly undulated, or even in places 

 twisted in irregular spirals, w/M false h-ancliing. 



I can discover no sufficient distinction between 

 Cladothrix and Streptothrix. Both are very doubtful 

 genera. 



49. C. dic/iotoma, Cohn. 



Threads repeatedly and regularly dichotomously 

 ranched, straight or slightly bent, about '3 yu thick, 

 rming small tufts of h or more mm. in diameter. 

 In putrid water, partly floating on the surface, 

 partly attached to algae. (Fig. 216.) 



The branching is here, just as with Cladothrix Fiirsten, only 

 apparent. A thread splits itself down the middle into two 

 halves, which lengthen independently, and thus grow side by 

 side, whereby the piece which was separated is pressed on one 

 side, and so appears as a branch. 



50. C, Fdrsleri, Cohn. 



Strcptothiix Forsteri, Cohn. 



Threads straight or bent, in places twisted in 

 irregular spirals, sparingly and irregularly branched, 

 separating into pieces of various lengths. 



In the lachrymal canals of the human eye, forming 

 tallowy or crumbling masses, which are yellowish- 

 white or blackish, 1 2-3'" long, and about l'" {i.e., 

 about 2 mm.) thick. (Fig. 217.) 



X. Myconostoc, Cohn. Threads very slender, 

 colourless, inarticulate, but on desiccation breaking 

 up into short cylindrical fragments, variously bent 

 and intertwined, stirrotiiided by gelatine, which forms 

 spheroidal masses of 10-17 fx (or more) in diameter. 

 Multiplication by constriction and bipartition of these 

 gelatinous masses. 



51. M. gregariiim, Cohxi. 



Gelatinous masses floating on the surface of putrid 

 water, singly or heaped into little slimy drops ; 

 exterior boundary sharply defined.* 



On water in which algae were decaying. (Figs. 

 218, 219.) 



W. B. Grove, B.A. 

 {To be continued.) 



* This species was recorded by Professor Lankester as a 

 phase of Spirillum undula (CJ. J. M. S., xiii. 424), but as no 

 genetic connection between the two has yet been traced Cohn 

 thinks It better, at present, to keep it distinct. It derives its 

 name from its analogy with Nostoc among the algs.— Tk 



MICROSCOPY. 



Meteorites. — The March number of the Journal 

 of the Quekett Microscopical Club has a paper on 

 " Fluid contents in Meteorites," by Mr. H. Hensoldt. 

 Can any reader tell me where to find any further in- 

 formation bearing upon the subject ? I have obtained 

 from Messrs. Watson & Son, High Holborn, several 

 slides of a meteorite, prepared by Mr. Hensoldt, 

 each showing moving bubbles very distinctly. The 

 discovery, if confirmed, upsets so many theories on 

 Meteorites, that there will, no doubt, be considerable 

 discussion on the subject, — //. M., Sidciip, Kent. 



Microscopical Notes. — The August number of 

 the American Monthly Microscopical Journal notifies 

 that the subject of uniformity in size and nomenclature 

 of eye-pieces was about to be discussed by one of the 

 American societies. Mr. Davis, in his excellent work 

 "Practical Microscopy," deplores the ,want of an 

 universal gauge for eye-pieces and sub-stage fittings- 

 While the matter is more or less before the public, 

 there is one phase of it to which attention may well 

 be redirected. Uniformity in size of oculars and sub- 

 stage fittings would be an immense boon to micro- 

 scopists residing at places far removed from manu- 

 facturing opticians, and who, if uniformity prevailed, 

 could from time to time add to their stock of micro- 

 scopical appliances by merely ordering the specific 

 articles they required. There are places not a 

 hundred miles distant from where I write, at which 

 one cannot get satisfactory adapters fitted, nor 

 additional sub-stage apparatus, nor a new ocular, nor 

 even a well-fitting camera lucida for a given eye- 

 piece, without sending some portion of a microscope, 

 in constant use, all the way from India to a London 

 optician. This state of things does not encourage 

 the use of the instrument. It involves great delay 

 and a double risk of transit, and also expense of 

 carriage which in no way benefits the opticians 

 themselves. I am not a stranger to these drawbacks, 

 and know that others are or have been in like plight. 

 The universal screw was a step in the right direction, 

 but there it only applies to objectives. What is still re- 

 quired is uniformity of gauge for oculars and sub-stage 

 fittings. Writing to you a few months back I drew atten- 

 tion to some of the difficulties which, in my humble ex- 

 perience, beset mounting in our hot and humid climate. 

 Since then I have got out a copy of Davis's Practical 

 Microscopy, and have tried balsam and benzol, and 

 dammar and benzol, following the recipes and pro- 

 cesses given by him. The benzol solutions really set 

 in about three to five weeks, and, without vacant 

 spaces showing themselves round the edge of the 

 thin glass cover, I may here mention that for baking 

 the balsam for the benzol solution, and indeed for 

 other processes where heat maintained for some time 

 is necessary, I use the oven compartment in one of 

 Rippingilles' kerosene oil stores, and find it after a. 



