230 



NATURE 



[December 22, 1910 



of the trypanosome of sleeping sickness to man by 

 G. palpalis. The discovery that the trypanosome of 

 sleeping sickness persists and grows in G. palpalis 

 is akin to the discovery of the development of the 

 malaria parasite in the anopheles. The discovery of 

 the transmission of the piroplasma of Texas fever, 

 of East Coast fever, and of "biliary fever" in stock, 

 by means of ticks, pointed the way to the discovery 

 of the transmission by ticks to man of the spirillum 

 of relapsing- fever. There may be some reason to 

 hope that the exhaustive investigation of the causes 

 of grouse disease which is now in progress may pos- 

 sibly lead to a better understanding of the causes of 

 appendicitis in the human subject. Many similar 

 instances might be mentioned. But this is not the 

 place for an essay on the recent history of bacterio- 

 logy. 



Much yet remains to be done. The cause of and 

 specific remedy for blackwater fever, that scourge of 

 tropical Africa, is still to seek. An effectual remedy 

 for sleeping sickness still makes itself desired. 

 Leprosy still baffles the investigator. No cure for 

 bilharzia has yet been found. Prophylaxis for horse- 

 sickness amongst horses, hitherto baffled by heemo- 

 lysis, has still to be discovered. (For mules a fairly 

 satisfactory prophylactic has been found.) Piroplasma, 

 for which, in dogs, a specific cure has been discovered, 

 in horses and cattle still presents an unsolved 

 problem. 



But the future is full of hope. Such great strides 

 in advance have been made during the last few years 

 that no difficulty seems, to the investigator, to be 

 insuperable. Perhaps the most interesting- of the 

 later developments is the discovery of a series of facts 

 which point to the probability of the terribly fatal 

 fever, hitherto called malaria, on the west coast of 

 Africa, being really a form of yellow fever. This 

 matter is now, or is shortly, about to be brought under 

 exhaustive investigation; and should the probability 

 turn out to be a reality, the adoption on the Coast of 

 precautions similar to those which have proved so 

 successful on the isthmus of Panama should render 

 the Gold Coast as healthy as Barbados. Small 

 wonder that an influentially signed address has been 

 sent to the Memorial Committee, suggesting that the 

 name of our beloved Sovereign, the late King Edward 

 the Seventh, cannot be better commemorated than by 

 a liberal endowment of the schools of tropical medi- 

 cine, which in these later years have done so much 

 for the promotion of bacteriological research and the 

 prophylaxis and cure of tropical diseases, both in 

 the United Kingdom and in the British Dominions 

 beyond the seas. 



THE MICROSCOPE AS AN OPTICAL 

 INSTRUMENT. 

 Microscopy. The Construction, Theory, and Use of 

 the Microscope. By E. J. Spitta. Second edition. 

 Pp. xxii + 502 + xvi plates. (London: J. Murray, 

 19 10.) Price 125. 6d. net. 

 ' I "HE views expressed in the previous notice of this 

 -L work which appeared in Nature (February 6, 

 1908) would appear to have been amply borne out in 

 the welcome accorded to it by the public, since a 

 NO. 2147, '^OL. 85] 



second edition has already become necessary. Continued 

 use of the volume as a book of reference has thoroughly 

 confirmed the original opinion formed as to its 

 value for the purposes of the practical microscopist. 

 While much more limited in scope than the classical 

 work of Carpenter and Dallinger, being restricted to 

 the consideration of the microscope as an optical in- 

 strument, it has from this point of view already largely 

 superseded the older work. Dr. Spitta is fortunate, 

 too, in having obtained, in dealing with the more 

 theoretical portions of the subject, the assistance of 

 Mr. Conrady, whose excellent mathematical know- 

 ledge has helped to keep the book free from any of 

 the remarkable theories in connection with the micro- 

 scope which have been put forward in recent years, 

 and have even found acceptance from some skilled 

 practical microscopists. 



One of the features of the first edition of the book 

 was that it was well up-to-date in the account given 

 of present-day microscopes and microscope construc- 

 tion and accessories. There was thus the less neces- 

 sity for changes in a new edition appearing after such 

 a comparatively short interval. Nevertheless, besides 

 the one or two more important additions of which 

 mention is made below, advantage has been taken of 

 the opportunity offered to include some of the most 

 recent work. Old illustrations of microscopes by pro- 

 minent makers have been replaced by others of the 

 newest types, and descriptions of novel accessory 

 apparatus are given. We note that the name of the 

 Spencer Lens Co., of Buffalo, N.Y., now appears for 

 the first time, their stand for critical work being fully 

 illustrated, and attention is directed to their one-sixth 

 objective with specially long working distance (i mm.). 

 A new sixth by Watson and Sons, and one by 

 Reichert, with extra long working distance, are also 

 mentioned. Illustrations of newer models by Zeiss, 

 Beck, and Watson take the place of those previously 

 given, and some forms of museum microscopes, with 

 mechanical contrivances for bringing a series of slides 

 successively into the field of view, are now described. 



Among additional accessory apparatus may be men- 

 tioned the simple form of apertometer devised by Mr. 

 F. J. Cheshire; new illuminators, especially the con- 

 venient miniature arc lamp by Leitz; Mr. J. W. 

 Gordon's lamp with glass-rod light collector, and Mr. 

 J. E. Barnard's mercury-vapour lamp for micro- 

 scopists — very convenient, with screens, for obtaining 

 monochromatic light ; a new auxiliary stage by Watson 

 and Sons; forms of gauges for measuring the thick- 

 nesses of cover glasses and slips; measuring oculars 

 or eyepiece micrometers ; and a simplified apparatus 

 and method of preparing metallurgical specimens for 

 microscopical examination. The last would appear to 

 be outside the limits of the work, which does not deal 

 with the extensive subject of the preparation of 

 specimens. We have noted also a number of changes 

 in the text, whether by way of omission of unnecessary 

 matter, or additions to render explanations clearer. 

 It is interesting that Dr. Spitta appears finally to have 

 come to the conclusion, with reference to the "black 

 dot " and " white dot " effects in pleurosigma, that 

 "the better the combination (objective) the better the 

 rendering of the black dot effect, no matter the appear- 

 ance, within reasonable limits, of the white one." 



