496 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
and meristem— always contains pectic substances associated with 
cellulose; the most widely distributed forms being pectic acid and 
pectose. 
Pectic acid is usually found combined with inorganic bases, most 
commonly lime. The ill-defined substance known as pectose is asso- 
ciated with calcium pectate in all the soft tissues, sometimes replacing 
it, especially in young tissues. The calcium pectate is found exclusively 
in the middle layer which separates the cells, cementing them together, 
and constituting the “ intercellular substance ” of Mohl. 
The detection of these substances is described in detail in a number 
of species of Equisetum and in a variety of flowering plants. It is 
insoluble pectates, chiefly of lime, that constitute the sculpturings — 
frequently in the form of rods or knobs, which so often mark the cell- 
walls which bound intercellular spaces. The substance which clothes 
the walls of intercellular spaces is also of this nature, and not proto- 
plasmic, as has been asserted by some authors. In some cases a portion 
of these deposits is capable of swelling up in water and becoming 
partially gelatinized. 
(2) Other Cell-contents (including- Secretions). 
Pigments of the lower Cryptogams.*— Prof. W. Zopf has studied 
the nature of the pigments in various Algae, Fungi, Lichens, Myxomy- 
cetes, and Schizomycetes. 
The properties are given of the haematochrome obtained from Trente - 
poblia Iolithus ; the author determined it to belong to the class of carotins 
(lipochromes). A table is given of the spectra of the various carotins. 
The colouring matter of various yellow lichens was investigated. 
From Cetraria Pinastri and G. juniperina , especially from the medulla, 
was obtained a resinous acid (“ pinastric acid”); Sticta aurata does not 
contain this acid, but a crystallizable pigment insoluble in mineral acids 
and alkalies (“ stictaurin ”). The red colour of the medulla of Physcia 
endococcinea is due to the presence of two crystallizable pigments of an 
acid character, “ rhodophyscin ” and “ endococcin.” Callopisma vitellinum 
yields two pigments, calycin and a new lemon-yellow “callopismic 
acid.” Calycin was also obtained from Acolium tigillare. A new yellow 
acid, “ placodic acid,” was obtained from Placodium fulgens and Calycium 
chlorinum. 
The orange-red pigment of Pilobolus Kleinii , oedipus, and crystallinus , 
insoluble in water, but easily soluble in alcohol, chloroform, and carbon 
bisulphide, is a lipochrome similar to that of Chroolepus and of Bacterium 
egregium. This yellow pigment was found to be taken up also by two 
parasites of the Pilobolus , Pleotrachelus fulgens and Endobiella destruens. 
Carotin was found also in certain insects belonging to the Chryso- 
melidem and Coccinellese, Lina Populi and Tremulse , and Coccinella sep- 
tempunctata and quinquepunctata. 
The fructification of Bulgaria inquinans was found to contain six 
distinct pigments, a red crystallizable pigment (“ bulgarin ”), a blue 
pigment (“ bulgarcoerulein ”), a yellow resin (“ bulgaric acid ”), a yellow 
* Beitr. z. Phjs. u. Morph, niederer Organismen, Leipzig, 1892, Heft 1, 
pp. 30-56 ; and Heft 2 (1892) pp. 3-32 (2 pis.). 
