128 



THE POPULAR SCIENCE MONTHLY. 



NOTES. 



Mechanism of Thought. An important 

 paper was read at the last meeting of the 

 Medico-Chirurgical Society of London on 

 this interesting but very complicated subject, 

 by Dr. Broadbent. His theory was based 

 partly on the results of his own dissections, 

 partly on remarkable cases of loss of speech 

 and paralysis that either came under his 

 own notice or have been recorded by others. 

 The chain of physical actions which he 

 claims to be implicated in the process of 

 thinking, can only be followed in detail 

 by the anatomist ; but the general sequence 

 of events on this theory is : the formation 

 of ideas in the marginal convolutions at the 

 summit of the sensory tract ; the employ- 

 ment of these in trains of thought in the 

 convolutions withdrawn from immediate re- 

 lation with the outer world ; the propagation 

 of excitations to the third left frontal con- 

 volution, leading to the selection of certain 

 sound-groups ; the coordination in the cor- 

 pus striatum of the muscular movements re- 

 quired to produce those sounds ; and, finally, 

 the transmission of impulses from the sev- 

 eral nuclei of the medulla oblongata to each 

 individual muscle required to be brought 

 into play. Academy. 



Aerial Navigation. Dupuy de Lome 

 gives a brief account of an aerial journey 

 made by the author in company with four- 

 teen others in a newly-constructed air-bal- 

 loon, and machinery for imparting to this 

 balloon and the car thereto attached any 

 desired direction or motion, independent of 

 that which the wind or air-currents will 

 give to the balloon. The experiment has 

 proved a complete success in every respect ; 

 a speed of 50 kilometres (31.065 English 

 miles) per hour could be readily obtained. 



Prof. Ehrenberg, who has published from 

 time to time the results of his examination 

 of those microscopic bodies that are carried 

 by the atmosphere and deposited as sub- 

 stances of a red color, has collected all the 

 observations on this subject made by him 

 between the years 1847 and 1870. This im- 

 portant memoir, consisting of 150 pages, two 

 tables, and two plates, will appear in the 

 forthcoming volume of the Transactions of 

 the Berlin Academy for 1871. He enumer- 

 ates all the instances of this phenomenon 

 which have been placed on record ; the earli- 

 est being a case of dust-shower which fell for 

 ten days in the Chinese province Honan, in 

 the year 1154 b. c. As his examination was 

 directed chiefly to organisms contained in 

 the showers, the analysis was entirely micro- 

 scopical, not chemical. The number of anal- 

 yses made by himself is altogether 70, and 

 he was able to distinguish not less than 460 

 distinct forms of organic life. Academy. 



If there were any reasonable question of 

 the value of vaccination as a preventive of 

 small-pox, strong evidence in its support ia 

 furnished by the circumstance of an epi- 

 demic now prevailing in the Island of Jersey. 

 It appears that, of 39 persons comprising 

 all who were attacked with small-pox in the 

 small town of Gorey, but five had ever been 

 vaccinated. Six of the 39 died, and but one 

 of these had ever been vaccinated. At last 

 accounts, the epidemic was rapidly spread- 

 ing, and under very favorable conditions 

 it would seem, for investigation has shown 

 that at least one-third of the children under 

 15 years of age in the whole island are un- 

 vaccinated. 



Nitrate of Ammonia in Respiration. 

 Dr. Struve states that, by breathing for 

 some moments in a large-sized beaker-glass 

 previously moistened with water, and next 

 rinsing the glass with some pure distilled 

 water, this liquid will be found, by the usual 

 tests, to contain ammonia and nitric acid. 

 This formation of nitrate of ammonia is 

 stated to become increased after dinner has 

 been taken. The author is of opinion that 

 atmospheric nitrogen is not entirely passive 

 in the process of respiration, but it should 

 be observed that this opinion is contradicted 

 by the direct experiments of Drs. Regnault 

 and Reiset. Chemical News. 



Dr. Livingstone's safety is not yet de- 

 spaired of by his brother, Mr. Charles Living- 

 stone, her Majesty's consul at Fernando Po. 

 This gentleman is no stranger to Africa, hav- 

 ing been long resident ou the west coast, and 

 travelled much about that portion of the con- 

 tinent. He is stated to be confident that 

 the doctor will, in the course of a few 

 months, reach the seaboard at or near Zan- 

 zibar, and to hold the fact of the opening 

 up of a new river on the west coast, between 

 Opobo and New Calabar, to be a proof that 

 Africa, even there, is only imperfectly known. 

 Lancet. 



Since attention has been directed to the 

 subject, cases of lead-poisoning, traceable to 

 the use of hair-preparations containing lead, 

 are found to be very frequent. A case of 

 this sort was recently reported in the medi- 

 cal journals, which was at first mistaken for 

 muscular rheumatism, and treated as such, 

 with but slight amendment. Paralysis of 

 the extensor muscles of the fingers and hands, 

 with " wrist-drop " coming on, the true na- 

 ture of the affection was seen, and its cause 

 readily found in the frequent use of a hair- 

 renewer containing a large proportion of su- 

 gar of lead. No lines were seen upon the 

 gums, but attacks of colic had been frequent. 

 Discontinuance of the hair-dressing, and a 

 resort to the ordinary remedies, soon effect- 

 ed a cure. 



