172 



HA RD WICKE S SCIENCE-G OSS I P. 



sovereign remedy. These parasites produce symptoms 

 of great debility, which may continue for years, 

 and often, sooner or later, terminate in death ; there 

 is also great bloodlessness produced, by the presence 

 of the worm in its human host. The worm occurs 

 mainly in hot countries. It is especially prevalent 

 in Brazil and in Egypt, where it causes the so-called 







m\ 



m 



Fig. 102. — Sclerostoma ditodcnale. a. Female, b. Male, 

 c. Actual length of parasite : c is a male worm. 



Egyptian chlorosis ; it is not uncommon in Italy. 

 It was unknown in Switzerland until, during the 

 progress of the works connected with the St. Gothard 

 Tunnel, it was discovered to be the cause of a serious 

 and fatal form of bloodlessness which largely pre- 

 vailed among the labourers. It thus acquired a new 

 and special interest in the eyes of Europeans. 



HOW TO MAKE A TINT-REFLECTOR. 



MANY persons who have a microscope, and 

 have not got a camera-lucida or tint-reflector, 

 very often would like to sketch what they see under 

 ihe glass, when they have no means of doing so. It 

 is for those I have written this short paper. 



The cost of this piece of apparatus is but very 

 trifling ; a little skill, and any one can make it. 



Get a wooden pill-box that, when the lid is off it, 

 will fit fairly tight on to the eye-piece of the micro- 

 scope (the lid I mean). Cut or bore a round hole 



in the centre (Fig. 103), the size~of the aperture, in 

 the top of the eye-piece. Now take two pieces of 

 thin wood — cigar-box, for instance, does admirably — 

 and cut two triangular pieces (Fig. 104), one side to 

 be 45 and the other 90 . Then cut with a fret-saw 

 a fine groove parallel to the 45 side, not too deep, 

 on one side of each piece (see dotted line, Fig. 104). 

 Then take some glue, and glue each triangle, with 

 groove inside each side of the circular hole in lid, 

 at the same time slipping in a thin glass cover 

 between the grooves, allowing it to work freely ; it 

 should then have the appearance of Fig. 105. If this 

 is done neatly, it will answer the purpose and 

 requirements of more expensive apparatus ; and if 



A 



Fig. 103. 



Fig. 104. 



Fig. 105. 



Fig. 106. 



the thin cover by any accident gets broken, it is 

 easily replaced. 



By turning the lid round and substituting a piece 

 of thin silvered glass, and using a fairly bright light, 

 the object can be cast down on to a sheet of white 

 paper and drawn that way ; or two or more persons 

 can examine the object at the same time. After 

 use the cover can be slid out, placed in the box, and 

 shut up. Fig. 106 is an end view : the outer black 

 circle is the box, centre circle the round hole. The 

 dotted lines show about the position the triangular 

 pieces of wood should go. 



P. S. — I have not given any measurements, because 

 variation of size of eye-pieces prevents me doing so. 



Croydon. Harry D. Gower. 



Dr. D. Draper shows that pneumonia is nearly 

 always coincident with a high percentage of ozone in 

 the atmosphere. 



Sir William Jardine's famous collection of 

 birds was sold at Leicester Square on June 17th. 

 Most of the type-specimens were secured for the 

 British Museum and the Cambridge University 

 Museum. 



