May 6. 1909] 



NA TURE 



273 



The determination of carbon is dealt with very well 

 indeed, and it is shown that the most trustworthy 

 method is that of burning the drillings mixed with red 

 lead in a stream of oxygen. This direct combustion 

 procfsi; has been in constant use in most of the 

 Slieftield works' laboratories for several years. Red 

 lead is at present, however, being largely discarded 

 in favour of pure manganese dioxide, which is in 

 nearly every case quite as effective, and more than 

 doubles the life of a porcelain boat. 



The concluding chapters of the book include one 

 on the examination of graphite and graphite crucibles, 

 and one on the annealing of steel. In the former, 

 the existence of silicon carbide in used plumbago 

 crucibles is considered, and an account given of the 

 determination of its amount. The chapter on the 

 annealing of steel, to which attention is specially 

 diiected in the preface, contains the extraordinary 

 statement that " rapid cooling of perfectly annealed 

 steel has no effect whatever on its hardness." The 

 author considers steel to be perfectly annealed when it 

 has been kept at 700-720° C. for from ten to twelve 

 hours, and states that it may then be cooled slowly 

 or quickly — in fact, it may be plunged whilst at 

 this temperature into cold water — without becoming 

 hard. This statement cannot be accepted. 



The book is very well printed, is singularly free 

 from typographical errors, and is provided with an 

 excellent index. 



The author may be interested, by the way, to learn 

 that the use of silver iodide indicators in the 

 cyanide titration of copper solutions was suggested 

 twelve years ago in the Chemical News. F. I. 



HYPNOSIS AND SUGGESTION. 



Die Hypnose und die Suggestion, Hire Wesen, ihre 

 Wirkttngsweise und ihre Bedeutung und Stellung 

 untcr den Heilmitteln. By Dr. VV. Hilger. Pp. 185. 

 (Jena : Gustav Fischer, 1909.) 

 '' I "HIS is a most interesting, scientific and readable 

 -L book. After a somewhat detailed historical 

 introduction, the author demonstrates in a clearer way 

 than we have hitherto read, that there is at least a 

 very close resemblance between normal and hypnotic 

 sleep ; indeed, one is left with the impression that there 

 is practically no difference between them. Inter alia 

 it is pointed out that there is an element of sub- 

 conscious thought even in normal sleep, and that this 

 is only partial (Teilschlaf) ; and, among other examples, 

 the oft-cited mother is instanced who sleeps soundly 

 through the noise of traffic or a thunderstorm, but 

 wakes at the feeblest cry of her new-born child. 



In discussing the nature of suggestion. Dr. Hilger 

 directs attention to what he calls mental (seelische) 

 reflexes, such as the flow of saliva at the thought of 

 food, contraction of the pupils on thinking of a bright 

 light, erection of the nipples and flow of milk when a 

 lactating mother thinks of suckling her child, and 

 so on. He also points out that memory-images are 

 stronger in normal sleep than during waking hours, 

 just as they are in hypnotic sleep. Some methods of 

 hypnosis are described, and it is rightly said that a 

 NO. 2062, VOL. 80] 



feeling of goodwill between the patient and the 

 physician is essential to successful hypnotism. 



In a chapter on suggestion and will, the author 

 insists on the importance of the movement-idea in the 

 performance of a voluntary action and on the coopera- 

 tion of expectancy of and practice in the particular 

 action. Instinct, motive, and interest are in turn 

 duly considered. 



The next chapter is devoted to a discussion of the 

 influence of the will, suggestion, and similar psychical 

 factors on disorders of perception ; and many interest- 

 ing cases bearing on the subject are reported, of which 

 the following is a typical example. A man was 

 aflflicted with a tickling in his throat shortly after 

 kissing his sweetheart, and he became convinced that 

 it was due to a hair in his throat. His doctor 

 examined the throat and found nothing more than a 

 slight pharyngitis, whicli was treated in the usual 

 way. Before the next visit, when the patient was no 

 better and still convinced of the presence of the foreign 

 body, the medical man had provided himself with a 

 hair, which he surreptitiously introduced into but 

 ostentatiously withdrew from the throat. The tick- 

 ling was instantaneously and permanently cured. 



In the last chapter, dealing with reflex disorders 

 and their treatment, the author first points out that 

 attention to a stimulus strengthens the reflex which 

 it excites, and he makes special reference to Haab's 

 cortical pupillary reflex. Many examples are then 

 given of the cure by hypnotism, &c., of such reflex 

 disorders as sea-sickness, the vomiting of pregnancy, 

 hiccough, nervous diarrhoea, nocturnal enuresis, 

 morbid blushing, palpitation, hay fever, nervous 

 cough, asthma, &c. It will be a surprise to most 

 people that the periods of menstruation may be modi- 

 fied by suggestion. 



The volume concludes with an account of some cases 

 of chorea and other functional disorders of the nervous 

 system successfully treated by hypnotism. There is a 

 good index, and we can cordially recommend the work 

 to those interested in the subject. 



THE STRUCTURE OF THE SCALLOP. 

 Pecten. By W. J. Dakin. Being No. 17 of the 

 Memoirs issued by the Liverpool Marine Biology 

 Committee. Pp. viii+136; 9 plates. (London: 

 Williams and Norgate, 1909.) Price 4s. 6d. 



THE scallop, clam or queen as it is called in, 

 different parts of our coasts is an animal of 

 considerable interest. To the pilgrims of the Middle 

 Ages who sought the famous shrine of St. James of 

 Compostella, the shell was both a badge and a 

 bowl, and from this old association it has become 

 iticorporated in many coats of arms, as, for instance, 

 in that of the city of Reading. More utilitarian 

 is the interest associated with the scallop as an 

 article of food, and in this respect the rare delicacy 

 of its flavour should bring " queens " into greater 

 favour than they now enjoy. To the more curious 

 inquirer the scallop offers many attractive features, 

 both in its structure and habits. The gem-like green 

 eyes that sparkle under the fringe of tentacles have 



