52 



THE AMERICAN MONTHLY 



[March, 



ary books it is not deemed necessary 

 to describe them here. It may be said, 

 however, that only perfect sections 

 should be preserved, and as a rule 

 these should be as thin as the tissues 

 will cut without injury to the cells. 



The good sections should be placed 

 in alcohol and allowed to remain in 

 that fluid for a day or two, in order that 

 resinous matters may be removed, 

 after which, if they are to be stained 

 they must be bleached. If, however, 

 it is intended to mount the sections 

 without staining them, they should be 

 transferred to clean and strong alco- 

 hol, then to oil of cloves, or to oil of 

 cajaput which is cheaper and quite as 

 good, and then mounted in balsam. 



The bleaching may be effected in 

 several ways, the one most commonly 

 employed is by means of Labarraque's 

 solution of chloride of soda, which 

 can be obtained from any druggist. 

 The sections should be placed in this 

 solution until they become quite white, 

 after which every trace of the solution 

 must be washed out with clean water. 

 The Labarraque solution destroys the 

 protoplasm and nothing remains but 

 the cell-walls. Another process of 

 bleaching sections is given on page 8 

 of Vol. II of this Journal. 



The processes for staining are 

 numerous, but in this, as in many 

 other things, the simplest and most 

 readily followed method gives results 

 quite equal to any methods that have 

 been proposed. If the reader will re- 

 fer to the process given on page 8i of 

 Vol. I of this Journal, he will find 

 one that has succeeded well, we be- 

 lieve, in the hands of every person 

 who has tried it, and the colors are 

 certainly very brilliant. All the other 

 methods that we have tried have pre- 

 sented greater difficulties than this 

 one, which, indeed, is quite simple. 



It is advisable for the novice to 

 begin with specimens that are well 

 adapted to double staining, such as 

 the softer stems with large cells, in 

 which hard and soft tissues are quite 

 distinctly defined, for with the hard 

 woody stems it is often difficult to ob- 



tain excellent results without consid- 

 erable experience. Nothing is more 

 satisfactory to begin with than a stem 

 of the pond-lily. Sections of leaves 

 are to be treated precisely like sec- 

 tions of stems. 



Form-cycle of Gloeocystis.* 



BY PAUL RICHTER. 

 {Continued.) 



In the long cylindrical cells, as long 

 as 12/^, which are usually enclosed 

 • in a cylindrical envelope, and which 

 I have, as already indicated, taken 

 for Gloeocystts monococca, Ktz., a cross 

 or diagonal division into two daughter- 

 cells takes place, which become sphe- 

 rical and remain at the ends of the 

 cell. Soon these surround themselves 

 with a special envelope, and repeat 

 the division. By the softening and 

 extending of the mother-cell wall, 

 the succeeding generations of cells 

 all remain within one envelope, and 

 in this manner produce the forms of 

 Gloeocystis vesiculosa, Nag., the fur- 

 ther description of which would be 

 superfluous. In the spherical cells 

 there is frequently seen a one-sided 

 arrangement of the chlorophyll, as 

 was also observed in the cylindrical 

 forms, so that the question arises 

 with me, whether it is necessary to 

 establish a new species. Notwith- 

 standing the circumstance that I find 

 this Gloeocystis so frequently in moist 

 forest ground and in similar places, it 

 may still be that it is a known species, 

 in which this one-sided arrangement 

 of the chlorophyll has been over- 

 looked. Otherwise it agrees with Gl. 

 vesiculosa. 



In its further course, from this 

 Gloeocystis comes a Palmella form, 

 which, if only a thin general envelope 

 was to be seen, would agree perfectly 

 with Glceocapsa stillicidiorum, Ktz., 

 Tab. Phyk. I. T. 20. The envelop- 

 ment, and forming of special envelopes 

 ceases, the daughter-cells lie free in 

 the mother jelly and repeatedly di- 



* Translated from Hedwigia. 



