146 
at tlie base of the spore is reflected over the upper surface of the cal- 
lose somewhat early, but fades out toward the center. At this time 
the extremity of the basidium is expanded funnel-form, and the callose 
septum is biconvex. Later the cellulose wall of the spore becomes com¬ 
plete, but in just what way the author was not able to determine. The 
expanded end of the basidium shrinks and finally becomes drawn out 
to a point by the time the spore falls, but, contrary to Cornu, the tip 
still retains its callose plug and is not covered by a cellulose wall. 
Reasoning by analogy, the author thinks the disarticulation of conidia 
in Peronosporse takes place by a uniform mechanism. The paper is 
followed by a good lithographic plate (in part 5). 
The following methods were employed to distinguish cellulose, callose, 
and protoplasm: Sections were first placed for some time in eau de 
Javelle* to remove plasrnic matters. They were then washed in water 
and placed on slides with the addition of some drops of an alcoholic 
solution of soda or very concentrated caustic potash. After ten or 
twelve minutes they were neutralized with acetic acid and stained. 
Cellulose is colored a beautiful blue by a concentrated solution of 
iodated phosphoric acid. The stain is deep and instantaneous, the 
treatment with alkalies rendering the cellulose easier to stain. For 
callose one of the blues formed of trisulphonated triphenylrosaniline 
and soluble in water should be used. Since some nitrogenous matters 
may yet remain, it is well to mix one of these blues with a solution of 
acid brown (Bismarck, Y esuvin, etc). This mixtureTnust always be used 
in an acid medium (acetic acid 3 to 100, formic acid 3 to 100). The cu¬ 
ticle and all azotic substances become brown, the cellulose remains 
colorless, and the callose becomes a brilliant greenish blue. After the 
action of this mixture, which requires some minutes, wash in water and 
mount in aqueous glycerine, in which the specimens will remain with¬ 
out bleaching for some months. Preparations treated with iodated 
phosphoric acid may be preserved in the same way and will keep for a 
long time if protected from the light. 
In a footnote the author recommends the following dyes as especially 
serviceable: (1) For protoplasm, lignin, cutin, and pectin compounds: 
Blue de diphenylamine soluble in alcohol, blue de Bayer soluble in alco¬ 
hol, bleu direct; bleu d’analine soluble in alcohol, bleu de gentiane 6 B., 
bleu opal, bleu de nuit, bleu lumiere. These blues do not stain callose. 
(2) For callose and protoplasm: Le bleu Nicholson OB., le bleu soluble 
BLSE, le bleu coton C4B, from the house of Poirrier et Dalsace at St. 
Denis; le bleu brillant verdatre pour coton, le bleu papier Y. from Bayer 
et Cie at Flers near Roubaix; les bleus alcalins OB, bleus nouveaux, G 
etR, from L. Cassella, Lyons $ bleu de Bayer DBF, from Badische Analine 
Soda Fabrik, Neuville sur-Saone. These colors are soluble in water. 
They stain protoplasm a deep blue and callose a greenish blue 5 also lig¬ 
nin slightly. They do not stain cellulose. (3) For pectin compounds: 
* Kaliumhypochlorite. 
