446 SECTIONAL TRANSACTIONS.—K. 
and that no lamina was developed. Further, had they occurred detached from 
the stems, they would certainly have been described as petioles of a fern or of a 
pteridosperm. It is interesting to note, however, that in the development of 
the leaves of the modern form Araucaria excelsa we have a very close parallel 
to that now recorded in this Carboniferous genus Pitys; and relationships 
between these two forms are not beyond the realms of possibility. 
7. Miss E. 8. Dowpina.—The Regional and Seasonal Distribution of 
Potassium in Plant-tissues. 
This paper deals with the occurrence of potassium in plant tissues as shown 
by the hexanitrite of cobalt and sodium, a reagent previously employed by 
Macallum in microchemical work on plant and animal tissues. On examining 
plants of contrasting physiological types, a characteristic potassium distribution 
was noticed for nearly every tissue. In some tissues this substance is most 
abundant, for example, in the ‘ crown’ cells below the spruce bud, and in the 
aleurone layer of the wheat grain, so that these tissues appear to act as storers 
of excess potassium. All meristematic tissues give a very dense reaction. 
In recording the seasonal variation of potassium in Piceuw canadensis, it was 
found that towards spring there was an increase in the amount in the conducting 
tissue, a redistribution of potassium witnin the bud, and a variation in the 
manner of distribution within the mesophyll cells. 
8. Mr. E. H. Moss.—Parasitism in the Genus Comandra. 
The genus Comandra is represented in Canada by four species, of which at 
least three are semi-parasites with a wide distribution and an extensive range of 
host plants The haustoria by which the parasite is attached to the underground 
parts of its host are in general similar to those described for other Santalaceous 
species. In the Rocky Mountains, Comandra livida is characterised by the 
occurrence in large numbers of variegated and more or less dwarfed individuals. 
Histologically the leaves of these abnormal plants exhibit features which are 
typical of mosaic diseases. 
9. Dean F. C. Harrison.—The Miraculous Micro-organism. 
An historical account of the red pigmentation of foods from B.c. 332 to the 
present. The nomenclature of the organism. [Taken as read.] 
10. Mr. J. L. Sacrer.—Soil Acidity Investigations Conducted in 
Switzerland and Devon. 
Determinations of the pH of soil filtrates made by the colorimetric method 
have shown that a definite correlation exists between intensity of light and soil © 
acidity i 
(A) Grand St. Bernard Region (gneiss, granite, schists)—alt. 1,100 to 2,700 
metres. : 
The results show definitely that in passing from the deep shade of the © 
Spruce Forest (pH 4.6) to the lesser shade of the Larch Forest (pH 5.1) and © 
then on to the open, we pass successively through soils of less and less acidity. 
Where the light is intense low pH values are rare, except in two special instances — 
where oxidation is necessarily deficient. These are (a) where the soil is shallow, — 
matted, and compact, and (b) where the soil is constantly wet. : 
(B) South Devon.—(1) Blackheath Wood, near Kenn, on Permian Breccia— 
alt. 200ft. Deepest shade under Prunus laurocerasus bushes pH 5.4, under 
Pinus insignis 6.4, and in Pedunculate Oakwood 6.6 and 6.8. 
(2) Stoke Woods, near Exeter, on Culm Shales—alt. 300 ft. Under Pinus 
sylvestris pH 5.1, Beech 6.0, Mountain Ash 6.3, and in Hazel Copse 6.7. 
(3) Pine Woods on Black Hill, Woodbury Common (Budleigh Pebble Bed)— 
alt. 540 ft. Deenest shade under Holly bushes pH 5.2, Pinus sylvestris 5.7, 
Pinus pinaster 6.0, and edge of Wood at roots of Hrica cinerea 6.3. 
Monday, August 11. 
11. Prof. E. C. Jerrrey.—The Present Status of the Biogenetic Law. 
The Biogenetic Law, or the Doctrine of Recapitulation, is one which has 
been the subject of repeated attacks upon the part of mutationists and mechanists 
