November 4, 1887.] 



SCIENCE. 



225 



also imported 3,211 hundredweight of husl<s and shells of the cocoa- 

 bean, which are also used up for cheap cocoa. There are about 

 ten chocolate and cocoa manufacturers in Holland, whose yearly- 

 requirements of cocoa-beans may be estimated at 3,000 tons, in 

 round numbers, principally of Guayaquil, Caracas, and Domingo 

 kinds. They mostly manufacture cocoa preparations, known by 

 the name of soluble cocoa, cocoatine, and cocoa-powder; viz., the 

 roasted and powdered cocoa-beans deprived of most of their natural 

 fat, or the cocoa-butter, which is used as a valuable ingredient by 

 manufacturers of chocolate and cocoa sweetmeats, and also for 

 pharmaceutical preparations. In the early part of last month no 

 less than twenty-five tons of this cocoa-butter was sold in Holland, 

 and fifty tons in London. The oldest of the Dutch cocoa-works 

 was founded on a small scale more than a century ago, and most 

 of the other works have existed from forty to sixty years ; but all 

 of them remained insignificant until the before-mentioned powdered 

 preparations found their way to foreign countries, especially Eng- 

 land and Germany, where certain Dutch brands of powdered cocoa 

 have been very well received- and enjoy a large sale. There are 

 people who suppose that the superiority of the Dutch cocoa-powder 

 is to be attributed to a peculiar mode of manufacture, different from 

 the methods followed in other countries. The idea to extract the 

 fat from the roasted cocoa-beans, and to sell the powder, is said to 

 have originated in the brain of a Dutch chocolate-maker about 

 1830. It is now generally practised in France and England. The 

 average consumption in the United Kingdom last year, per head of 

 the population, was, of cocoa, 0.41 pounds ; coffee, 0.86 ; tea, 4.87. 

 Tea brings into the revenue ;/;4,5cio; coffee, only ^£200,000; and 

 coffee mixtures and chiccpry, ^5,273. The latter seem to be de- 

 clining. 



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Recent Methods in the Study of Bryozoa. 



In Science for Oct. 7, Prof. Joseph F. James refers to certain 

 new methods in the study of Bryosoa, and doubts their efficacy in 

 classification ; he also refers to a forthcoming publication which 

 shall make this clear. Pending the publication of this paper by 

 my esteemed friend, I cannot help expressing my decided approval 

 of the methods he calls in question. Theoretically, development 

 has proceeded in two lines, — one internal, to accommodate itself 

 to the needs of internal function ; and one external, to accommo- 

 date itself to environment, to the world with which the being 

 comes in contact. Variations of function are far less frequent 

 than those of environment : hence internal structure may still be 

 very similar when external features have already extensively varied. 

 Hence internal structure usually furnishes the reliable characters, 

 which distinguish genera and higher groups ; external features are 

 used for specific determination. 



Very few -who have practically attempted the classification of 

 paleozoic Bryosoa into genera as defined according to the old 

 method have failed to see that such genera contained heterogeneous 

 assemblages of forms, often ran into each other, and contained no 

 distinct positive characters which were useful when great numbers 

 of Bryosoa were to be classified. The new method has furnished 

 solidity to this structure. The species fall into easily recognized 

 groups, as distinct as those of other organisms on the same scale of 

 development ; all this simply because of the abandonment of external 

 characteristics in the distinguishing of genera, for those of an inter- 

 nal nature, made easily accessible by the slide and the microscope. 



In this department of study. Prof. H. A. Nicholson took the first 

 decided stand, and is still contributing at short intervals valuable 

 papers on this interesting group of fossils ; but I believe that to 

 one of our fellow-countrymen, Mr. E. O. Ulrich, belongs the credit 

 of the perfection of this system. His work, which expresses his 

 matured views on this subject, is now in the press, forming a part 

 of Vol. VIII. of the forthcoming ' Illinois Report.' By his kindness 



I have been permitted to see plates, and furnished with private 

 extracts from the same, and I feel free to say that it will be a mon- 

 umental work in history of the study of Bryozoa. 



The practical test of the theory of development, which holds 

 good everywhere else in animated nature, is also satisfactoiy here.. 

 Instead of artificial we have natural classification, and that also of 

 a more definite and practical form. It remains to be seen whether 

 microscopic sections are sufficient to determine the species. A 

 circumstance peculiar to Bryozoa makes this in almost all cases 

 possible. The form, size, and arrangement of cells may be readily 

 seen in tangential section ; the presence of interstitial cells may 

 also be thus discovered ; whereas the little elevations or low spines 

 around the apertures of some cells may be seen in the sections as 

 spiniform tubuli. Elevated patches of cells may usually be recog- 

 nized by the local increased size of cells in the sections, and macu- 

 lae will be shown by judicious longitudinal sections. 



It remains to be seen what characters of specific importance can- 

 not be shown in microscopic sections. One of these is the size of 

 the specimen ; another, its method of branching ; a third, its gen- 

 eral contour. These may all be expressed by a simple drawing,, 

 taking no cognizance of individual cells. Besides the details above- 

 referred to, microscopic slides will of course furnish numerous others- 

 referring to internal structure alone. The fact, however, is, that not 

 only do microscopic slides reveal the characteristic features of the- 

 surface, but they often reveal them in a much better way than the 

 specimens at hand ; for these may be abraded, perhaps ever so lit- 

 tle, but just enough to rub away the little spines, or to remove the 

 walls of interstitial cells, and, by thus exposing the diaphragms of 

 the same, lead to the conclusion that they do not exist. Any one 

 who has ever looked over a quart-measure of specimens without 

 finding one suitable for description will know what this means. 



As regards the publication of Mr. Foord, ' Contributions to the 

 Micro-Paleontology of the Cambro-Silurian Rocks of Canada,' it is 

 an excellent exemplification of the tnethods (for this is what Pro- 

 fessor James criticises) of the advanced school of students of the 

 Bryozoa, and is a practical recognition of the merits of a work done 

 by an American paleontologist. All of the species figured are ac- 

 companied by magnified sections ,of the same, and all except 

 MonticuUpora Westoni have also figures of the specimen's natural 

 size; and perhaps the shape of that species, " Zoarium irregularly 

 hemispherical," would not be difficult to grasp by the working 

 paleontologist. The fact that Prof. H. A. Nicholson, immediately 

 after the separation of Mr. Foord from the Geological Survey of 

 Canada, was pleased to publish papers conjointly with that gentle- 

 man, serves to show what that eminent authority's opinion as to 

 the merits of Mr. Foord's specific work was. 



These remarks I hope represent fairly the claims of the new 

 school as to the advantages of their methods of study. One ob- 

 servation alone remains to be made. I suppose that Professor- 

 James was not in earnest when he objected to the new method on 

 account of the difficulty of making slides, no more than the physi- 

 cist who should object to the advance made in his science simply on 

 account of some of the refined mechanisms now used in his depart- 

 ment, no more than the student of Entomostraca who should ob- 

 ject to the classification reached in his science from the difficulty in 

 finding a specimen which is willing to be quiet enough to let itself 

 be accurately drawn. He simply expresses the difficulty he finds in 

 leaving his old methods of study and adapting himself to new ones, 

 and this accidentally escaped into print, not in the form in which he 

 would be willing to have it remain at second thought. But the 

 truth IS, that microscopic slides are not difficult to make. Messrs. 

 W. F. and John Barnes of Rockford, 111., manufacture an instru- 

 ment which I know from experience to be both cheap and useful. 

 The specimen to be cut is ground with emery until a plane is 

 formed having the same direction as the intended section. Then 

 successively finer grades of emery are used until a fine polish is ob- 

 tained, which can be made very fine indeed by using polishing- 

 po-wder sprinkled over a piece of plate glass. Then the specimen 

 is carefully washed, dried, and glued with Canada balsam to the 

 slide which is to retain the specimen. Then the specimen is ground 

 away until only a thin sheet remains fastened in the Canada bal- 

 sam, after which it is again smoothed, washed, and protected by 

 a thin cover-glass. Forty to sixty slides can be made in a day^ 



