JULV 25, 1895] 



NATURE 



291 



mony to the efficiency of the plate-columns ; whether in 

 all respects they will achieve the results their inventor 

 claims for them, it is, perhaps, yet premature to say. 



The chapters on the black ash process, on the manu- 

 facture of finished soda, and on caustic, are examples of 

 what has been said above as to Dr. Lunge's care and 

 industry ; Exhibiting no striking changes, they are yet 

 charged with additional matter, of which no satisfactory 

 account can be given, but which will become continually 

 evident to those using the book. 



The recover)' of sulphur from tank waste is, of course, 

 treated at length. The multitude of attempts to solve this 

 problem, the repeated failures — chemical or economic — 

 of these attempts, the apparent hopelessness of further 

 discovery in so well-explored a field, and the tenacity with 

 which the attack has been continued, form one of the 

 most interesting chapters in the history of manufacturing 

 chemistry, and the account gi\en here is full and accurate. 

 Though the detailed description of Schaffner and Helbig's 

 process has been omitted from this edition, yet the bulk 

 has swelled by some forty pages, an increase due, of 

 course, chiefly to the Chance-Claus process, the account 

 of which, with its modifications and variations, is one of 

 the best written portions of the book. How far this 

 beautiful process affords a satisfactory solution of the 

 problem of sulphur-recovery, may be gleaned from the fact 

 that in 1893 the produce of Chance sulphur in Britain 

 was estimated at 35,000 tons. 



An indication of the tendency of chemical manufacture 

 to become more scientific, to be guided by principles 

 rather than by rule-of-thumb, is found in the increased 

 amount of "theory" in the book. Not only have we 

 accounts of investigations into the reactions involved in 

 the ^various 'processes, but also accounts of the thermo- 

 chemistry of the Hargreaves process and the black ash 

 process, and of Dr. Hurter's application of mathematics 

 to technology, mentioned above. No one will dispute Dr. 

 Lunge's statement that manufacturing conditions are 

 complex, and difficult to imitate in laboratory experiments, 

 still more to state in a form definite enough for mathe- 

 matical expression : no one will question the justness of 

 his warning against proceeding too rashly on lines sug- 

 gested by theory alone, or indicated by mathematical 

 reasonings on insufficient bases ; but the fact that thermo- 

 chemistry and mathematics find a place at all in such a 

 work as this, shows that our manufactures are being con. 

 ducted with a closer knowledge than formerly of the 

 principles — chemical, physical, and mechanical — which 

 underlie them, and that we may look forward to a time 

 when we shall have as full control over the conditions of 

 our operations in the manufactory as we now have in the 

 laboratory. 



The Lcblanc soda process is regarded, by those who 

 are in any way connected with it, with feelings akin to 

 those with which they look on the British Constitution. 

 It inspires a certain affi,'ctionate respect, from its com- 

 bined familiarity and antiquity ; and the contemplation of 

 its decay or extinction gives rise to feelings of regret, 

 apart altogether from the pecuniary interests which are 

 involved in it. The statistics given by Dr. Lunge, which 

 show a steady increase in the salt used for the ammonia 

 process, from 27,000 tons in 1880, to 350,000 in 1S95, while 

 that used for the Lcblanc process has decreased in the 



same period from 650,000 to 470,000, are not reassuring ; 

 but if the older process be doomed to ultimate extinction 

 it will at least ha\e a worthy monument and history in the 

 successive editions of Dr. Lunge's book. 



Misprints and slips in such a work are inevitable ; 

 there are several, but nearly all such as betray 

 themselves at once, and carr>' their corrections on their 

 faces. A copious index to the volume adds greatly to its 

 value for reference. J. T. DUNN. 



PHYSICAL ANALOGUES OF PROTOPLASMIC 



MOVEMENT. 

 Microscopic Foam and Protoplasm. By Otto Biitschli. 

 Translated by E. A. Minchin. (London: Black, 1894.) 



PROF. bOTSCHLI'S work on Microscopic Foams has 

 been already discussed in these columns ; and 

 therefore, in noticing the English translation, a very short 

 account of the book itself will suffice. From his long 

 series of observations, especially upon the structure of 

 the protozoa, the author was led to regard protoplasm 

 as a substance arranged always in the manner of an 

 exceedingly minute honeycomb, containing a second 

 substance in its cells. Taking this view of the structure 

 of protoplasm, and probably stimulated by the experi- 

 ments upon capillarity and surface-tension made by his 

 colleague Prof Quincke, he next endeavoured to find a 

 substance having an analogous physical structure, and to 

 produce in it some of the simpler phenomena of proto- 

 plasmic movement. The result was the manufacture of 

 the remarkable foams, now- so well known in zoological 

 laboratories, in which the walls of the protoplasmic 

 honeycomb are represented by thin lamin e of olive oil, 

 the chambers containing a solution of potassium car- 

 bonate and soap. The remarkable resemblance between 

 the histological structure exhibited by drops of this sub- 

 stance, and that of an amceba, is probably familiar by 

 this time to most biologists, as is the resemblance 

 between the streaming movements of the two structures, 

 and the protrusion and retraction of pseudopodia by each. 

 In the work before us, the final investigations upon oil- 

 foams are first described. The first eighty pages contain 

 a minute description of the manner in which the foams 

 are best prepared, and of their behaviour under the 

 influence of various agencies. Especially interesting is 

 the effect of induction shocks, by which convulsive move- 

 ments are obtained, and the streaming is frequently 

 slowed down or depressed. It is difficult to avoid com- 

 paring the manner in which such a foam-drop flows 

 towards a solution of certain substances, such as soap, 

 with the simpler phenomena of " chemiotaxic" attraction. 

 After a detailed description of the preparation and 

 behaviour of oil-foams follows a summary of investiga- 

 tions on the structure of protoplasm, as seen in the living 

 condition and after various methods of preparation. This 

 account deals with the structure of various protozoa, and 

 with the cells of many metazoon tissues, especially with 

 nerve-cells and fibres ; the object of the whole account 

 being to demonstrate the " alveolar " structure of the 

 protoplasm in all these cases. This account is illustrated 

 by several plates, which have been admirably re.-drawn 

 for the English edition of the work, and in addition to 

 these a collection of photographs has been prepared 



NO. 1343, VOL. 52] 



