2.56 



NATURE 



[August 24, 191 1 



Prof. Emil Rohde (in Zeitschr. f. wiss. Zool., Bd. 

 xcviii. , 1 Heft) shows that chromatin diminution occurs in 

 various tissues other than the germ cells. In the blood 

 cells of various vertebrates the nuclei undergo a matura- 

 tion process similar to that exhibited in oogenesis, portions 

 of chromatin being cast out of the nucleus and out of the 

 cell. In the red blood cells of mammals this process goes 

 on to such an extent that the whole nucleus is lost. The 

 nuclei of other tissue cells, especially those of the central 

 nervous system of vertebrates, exhibit diminution of 

 chromatin which the author compares with that observed 

 in spermatogenesis. The nuclei of the nerve cells in karyo- 

 kinetic division give off spherical masses of chromatin, 

 which later lie between the resting nuclei. In other cases 

 the nucleus breaks up into several small daughter nuclei, 

 which Prof. Rohde compares with the division of the sperm 

 mother cell into spermatozoa. The fact that diminution 

 of chromatin takes place in so many different tissues and 

 animals (those investigated range from Mustelus to man) 

 indicates that it has a general significance ; the author 

 regards it as a characteristic of adult, that is, of maturing 

 and dividing cells in general. Other memoirs in the same 

 journal deal with the innervation and sense organs of the 

 wings of butterflies and the nephridial funnels of earth- 

 worms. 



To The Journal of Economic Biology for July Dr. 

 H. B. Fantham contributes an important article on cocci- 

 diosis in game-birds and poultry. Owing, it is suggested, 

 to the great increase of motor traffic, and the consequent 

 pollution of the air in many parts of the country, white 

 diarrhoea and other forms of coccidiosis, which chiefly 

 affect young birds, appear to be on the increase, and there 

 is, accordingly, urgent reasons that every available means 

 should be taken for keeping them in check. The two 

 important objects which should be kept in view are, first, 

 the taking of such precautions as will tend to prevent the 

 pollution of air and soil by coccidian oocysts, and, secondly, 

 to endeavour to raise the vitality of young birds, and 

 thus enable them the better to resist the onset of the 

 disease. In the case of domesticated poultry, cleanliness 

 is a matter of the first importance, both as regards the 

 young birds themselves and their surroundings ; and it is 

 probable that if such preventive measures were properly 

 enforced and carried out, coccidiosis would eventually dis- 

 appear. The author gives a full and detailed account of 

 the structure and life-history of the parasite of coccidiosis 

 and of its effects on the intestinal tract of its victims, 

 but these are too long and too technical for quota- 

 tion, even in brief abstract, on this occasion. Eymeria 

 avium, or Coccidium avium, as it was formerly called, is 

 a minute animal parasite belonging to that section of the 

 Protozoa known as the Sporozoa, on account of the pro- 

 duction of resistant spores. Although in some cases the 

 whole intestinal tract of the bird may be riddled by the 

 parasite, the duodenum and the paired caeca, or blind guts 

 (especially long in grouse), are the parts chiefly attacked. 

 The life-cycle of the parasite is complicated by the fact 

 that there are two distinct phases of development, namely, 

 an asexual phase, known as schizogony, during which 

 there is a multiplication of the parasites by fission in the 

 lining of the intestine of the infected bird, and subsequently 

 a sexual phase, in which resistant cysts and spores adapted 

 for life outside the body are produced in myriads. It is 

 by these spores, which are swallowed by fresh birds with 

 their food and drink, that the disease is spread. 



The difficulty of obtaining trustworthy data, at any rate 

 in India, to prove or disprove the influence of forests on 

 atmospheric and soil moisture is reasonably argued in an 

 NO. 2l82, VOL. 87] 



article appearing in The Indian Forester (July). Not the 

 least interesting portion is the transcript of a note on the 

 subject submitted to the Indian Government by Dr. 

 Walker, the Director-General of Observatories. It ref 

 great credit upon the Government of India that, in spite 

 of opinions mainly adverse, they assent to the initi 

 of a few experiments in selected localities for the purpose 

 of tabulating information with respect to local differem es 

 in rainfall, temperature, and humidity inside and outside 

 forest areas, as also to differences in level of the under- 

 ground water table and extent of floods that might be 

 reTerable to the proximity of forest areas. 



An account of the Percy Sladen Memorial Expedition 

 (1910-n) to the Orange River through Little Namaqua- 

 land, contributed by Prof. H. H. W. Pearson, is appear- 

 ing as a series of articles in The Gardener's Chronicle. 

 In the current number (August 19) the author touches on 

 the existence of a flora with a strongly marked Cape 

 affinity occurring on the Khamiesberg range, while the 

 low country shows entirely different vegetative formations, 

 in which succulents predominate. The Khamiesberg is one 

 vegetative island, while another is found on the Huilla 

 plateau in South Angola, and possibly similar floras will 

 be discovered on the unexplored peaks in German South- 

 West Africa. If these islands show the remnants of a flora 

 once continuous, whence, it is asked, and by what route, 

 came the ancestors of the plants occupying the low-lands. 

 The illustrations represent some of the more striking 

 succulents, such as Mesembryanthem digitiforme and Augea 

 capensis. 



Owing to the receipt of numerous specimens of inflores- 

 cences from the graft hybrid. Laburnum Adami, sent to 

 Kew Gardens for identification, Mr. W. J. Bean con- 

 tributes a short article on the subject to The Kew Bulletin 

 (No. 6), in which he explains how this particular novelty 

 arose as a chance development from a graft of the dwarf 

 purple broom, Cytisus purpureas, on the common 

 laburnum. From the graft there arose a shoot which 

 produced the intermediate type of purplish-yellow flower. 

 Subsequently portions of trees propagated from the shoot 

 reverted to the parent types, so that a single tree may bear 

 at the same time the purplish flowers of the presumed 

 hybrid, yellow flowers of the laburnum, and purple 

 flowers of the broom. Two further examples of graft 

 hybrids, Crataego-mespilus Dardari and Crataego-mespilus 

 Asnieresii, are also described. They both arose on the 

 same tree, a medlar grafted on a stock of common 

 hawthorn, as branches showing composite characters. 

 Crataego-mespilus Dardari has shown a tendency to break 

 up into three forms, representative of the type Asnieresii, 

 pure medlar, and itself. The different forms are illustrated 

 from a photograph of three spraj'S gathered last June from 

 a specimen of Crataego-mespilus Dardari growing in Kew 

 Gardens. 



In the August number of Petermann's Mittcilungen Prof. 

 Maurer describes a conventional projection for conveniently 

 representing the lines of magnetic declination. For their 

 study Mercator's projection is unsuitable, however well 

 adapted it may be to the requirements of the navigator, 

 since the areas in the neighbourhood of the poles are not 

 represented, and the zones in higher latitudes are greatly 

 distorted. In his projection the polar regions are well 

 shown, the central point of the map being in #=o°, 

 \ = 90° E. South America is considerably distorted from 

 being unfavourably placed, but other continents suffer less. 



The Journal of the Meteorological Society of Japan for 

 June contains original articles, with brief abstracts in 

 English, (1) on the construction of protected rain-gauges, 



