THE JOURNAL, OF PHARMACOLOGY. 29 



is not always the case, and very faint colorations can be detected micro- 

 chemically only. Of the various chemical reactions, those for Hgnin (sul- 

 phate of anilin, phloroglucin and hydrochloric acid, or indol and hydro- 

 chloric acid) alone can be used niacro-chemically for the determination of 

 fibers in paper. In general, however, these reactions do not show the 

 presence of any particular fiber, but indicate only the existence of varying 

 degrees of lignification. Accordingly, these lignin tests demonstrate the 

 presence of lignified fibers, but do not tell how much is present nor the 

 nature of the fibers. This is so much more the case since the same kind 

 of fiber may or may not show lignification according to the treatment 

 undergone, for certain chemicals (alkalies, acids, bleaching materials) de-' 

 stroy the lignin. 



When two or more kinds of fibers are mixed, their relative proportions 

 can be ascertained only by means of the microscope ; namely, by careful 

 counting. 



Examination of the Fiber. 

 In examining paper for its fiber it is only necessary to cut ofi" a very 

 small sample, which is then moistened with water, or a mixture of equal 

 parts of alcohol, 95/0, water and glycerine, and carefully teased. There- 

 upon the fiber may be examined in the examining fluid under the cover- 

 glass. Care should be taken to tease the sample carefully in order not to 

 tear the fibers, for the latter should be examined in a condition as similar to 

 that in which they exist in the paper as possible. Obviously the previous 

 thorough softening of the paper in water is quite necessary. 



The number of kinds of fibers that may occur in paper is very large. 

 The coarser papers may be made of almost any fibrous mass. 



At the present time, plant fibers almost exclusively are used in the 

 manufacture of paper, since animal fibers, even after having been used 

 several times, can be used to better advantage for other purposes, for in 

 general they add greatly to the expense of the paper. 



In foreign papers one finds a great number of strange fibers whose recog- 

 nition is very difiicult.-'- Inf general, however, the papers ordinarily found 

 in the market contain the following fibers : Cotton, linen, hemp, jute, 

 corn-husk, cereal straws, esparto straw, bamboo, rice-straw, woods (pop- 

 lar, cedar, pine, etc.), mulberry-tree bast, sunn fiber, bast of I^agetta Lin- 

 tearia. The expressed and extracted stalk of the sugar cane is also an im- 

 portant raw material in the fabrication of paper. 



In the majority of papers one finds only linen, cotton, cereal straw, and 

 wood fibers. The other above mentioned raw stuffs, and many others, are 

 rarer. Still in research work esparto, bamboo, jute, corn-husk, rice, mul- 

 berry, and hop fibers are of importance. 



*Royle. The Fibrous Plants of India. London. 1855, p. 392. 

 t Wiesner, J. Oesterr. botan. Zeitschrift. 1864, No. 3. 



