April io, 1913] 



NA'l URE 



145 



I 1 ral dates, he publishes a series of photographs 



of its form, displaying the remarkable changes which 

 the tail underwent. 



Franklin Adams Chart of the Sky. — The Roval 

 Astronomical Society has undertaken the publication 

 of a limited number of reproductions of the Franklin- 

 Adams chart. The 206 sheets form a complete map 

 of the whole sky, the area of each being" 15 by i^°. 

 It will be remembered that the original plates were 

 secured with a 10-in. Cooke triplet objective of 45 in. 

 focal length ; the negatives show stars down to the 

 sixtei nth and seventeenth magnitudes. The repro- 

 ductions will be on bromide paper, 15 by 12 in., the 

 chart area being 11 by 11 in. The complete price 

 will be ten guineas, and it is expected that the first 

 sets will be ready for delivery in twelve months' time. 

 It is hoped that a sufficient number of subscribers will 

 be enlisted to help to defray the cost of such an expen- 

 sive undertaking. 



A Cheap Form of Grating Spectrograph. — In the 

 current number of Knowledge (vol. xxxvi., No. 537, 

 p. 142) Mr. A. H. Stuart describes what seems to be 

 a new form of spectroscope in which a transmission 

 grating is used. The instrument is there illustrated 

 by two diagrams, and the principle involved can be 

 easily grasped. The instrument is of the rectangular 

 box form, having the slit and camera at one end of 

 the box. The light, after passing through the slit, 

 falls on an objective, at the back of and nearly in 

 contact with it being placed a replica grating ; behind 

 this grating is placed a plane mirror at a distance of 

 a few inches. The beam of light passes through the 

 slit to the objective, and falls normally on the grating. 

 A large portion of the light passes through the grat- 

 ing' unchanged, and falls on the mirror. If it meets 

 the mirror normally it will be reflected back to the 

 grating, and a spectrum will pass out obliquely 

 through the object glass and fall on the photographic 

 plate at the camera end to one side of the collimator. 

 In order to avoid the faint reflection spectrum the 

 grating is retained in its position at right angles to 

 the incident beam, but the mirror is slightly twisted. 

 Thus a pure spectrum of considerable dispersion is 

 obtained. Mr. Stuart has constructed such an appa- 

 ratus by the judicious use of 20.«., the achromatic 

 lens, 2 in. in diameter, costing 3s. 6d., and the grating 

 10s. 6d. 



Khedivial Observatory, Helwan. — Two bulletins, 

 Nos. 8 and 9, from this observatory indicate the use- 

 ful astronomical work that is being accomplished in 

 Egypt. The first gives an account of the method 

 adopted and the results obtained in determining the 

 astronomical positions of El Daba'a, Mersa Malruh, 

 Baqbaq, Solium, and Siwa. The work was carried 

 out by Messrs. E. B. H. Wade and H. Knox Shaw. 



The second of the two bulletins contains the results 

 of the first three years (1909-11) of nebular photo- 

 graphy with the Reynolds reflector obtained by Mr. 

 H. Knox Shaw. It is stated that during this period 

 the instrument was constantly undergoing alterations 

 and repairs, so that some of the plates are not so good 

 as they might be. Nevertheless, some of them afford 

 considerable information as to the structure of some 

 nebula? not hitherto photographed. The table gives 

 the new general catalogue numbers, the positions for 

 1900 and remarks, and four plates, each containing 

 four or more reproductions, conclude the publication. 

 Attention is directed to the advantage of making 

 drawings of the smaller and less brilliant nebulae from 

 the negatives, a method which is capable of repro- 

 ducing the general form of the nebula almost as 

 accurately as any photographic reproduction. 



THE DEVELOPMENT OF THE PAR ASHE 

 OF INDIAN KALA-AZAR. 



IN a recent memoir with the above title, 1 Captain 

 VV. S. Fatton gives a detailed account ot investiga- 

 tions carried on by him in .Madras upon the develop- 

 ment and transmission ut the parasite ot Kala-azar, 

 commonly known as Leishmania donovani. As the result 

 of numerous experiments with various bluod-sucking 

 insects, the author concludes that the transmission ot 

 Indian Kala-azar from man to man is effected solely 

 by bed-bugs of the genus Cimex, and finds that the 

 parasite develops as readily in C. lectularius, the 

 species common in Europe, as in the Indian species, 

 C. rotundatus. The development observed by the 

 author takes place entirely in the digestive tract of the 

 bug, and is in the main as follows. 



The bug takes up the parasite from an infected 

 person in the leishmanial form, that is to say, as the 

 familiar " Leishman-Donovan body," contained either 

 within white blood-corpuscles or in macrophages, in 

 the peripheral blood. After being ingested by the bug, 

 the parasites remain in an unchanged condition for 

 some thirty-six to forty-eight hours. The earliest 

 developmental changes in the gut of the bug may 

 take place while the parasite is still enclosed in a 

 leucocyte or after it has been set free by disintegration 

 of the host-cell, and consist of an increase in the size 

 of the parasite, with enlargement of its trophic and 

 kinetic nuclei. As growth proceeds, the parasites may 

 multiply by binary fission. 



The next event in the development of the parasite is 

 the formation of a flagellum, which takes place from 

 the third to the fifth day after the last feed of infected 

 blood. A young, growing parasite may, without 

 dividing, become elongated and spindle-shaped, and 

 acquire a flagellum ; or it may first multiply by binary 

 fission, after which each of the two daughter indi- 

 viduals acquires a flagellum ; or the parasite may go 

 through a process of multiple fission, in which the 

 two nuclei, trophic and kinetic, divide each into eight 

 or more, and as many flagella grow out, with subse- 

 quent division of the body into a number of flagellated 

 daughter-individuals. However the details of the 

 process may vary, the final result is the same, and 

 by the fifth day the parasites, considerably increased 

 in number, have the form of long, actively moving 

 flagellates of the Herpetomonas type, familiar to all 

 those who have studied the development of the parasite 

 in artificial cultures ever since these changes were first 

 discovered and described by Rogers. 



About the sixth or seventh day the flagellate para- 

 sites are observed to be attaching themselves by their 

 flagella to the intestinal wall of the bug. When thus 

 attached, the body of the parasite slowly rounds up 

 and at the same time it divides ; the smaller forms thus 

 produced divide again, and meanwhile the flagellum 

 becomes shorter, and finally disappears altogether. 

 The result of these changes is that the parasite reverts 

 again from the herpetomonad phase to the form of the 

 small, non-flagellate leishmanial body, distinguished by 

 the author as the " post-flagellate " phase, though it 

 does not appear to differ in anv essential detail from 

 the initial "preflagellate " leishmanial form, but is 

 described as having a distinct envelope ("periplast"). 

 The post-flagellate stage in the bug begins about the 

 eighth day, and is completed by the twelfth. 



According to Captain Patton, this post-flagellate 

 stage represents the final stage of the de- 

 velopment of the parasite in the bug. He 



NO. 2267, VOL. 91] 



