TOME II, 1904. 
ON THE LOCALISATION OF ALKALOIDS IN PLANTS. 187 
4. By means of the microchemical tests many new alkaloid- 
plants have been discovered, the result being afterwards confirmed 
by the usual chemical methods e. g. certain Orchidaceæ (where 
alkaloids were formerly quite unknown), Amaryllidaceæ, Papave- 
raceæ, Ranunculacee, Solanacee, etc. 
5. Although the investigation of animal tissues is particularly 
delicate, observations (yet unpublished) show that even here a 
microchemical identification of organic bases is sometimes possible 
— for instance, in Salamandra. 
6. Granting that the physiology of alkaloids is far from settled, 
[ think a critical study of their topography as well as their beha- 
viour in germination, growth, etiolation, maturation of seeds, etc., 
supports the view that they are waste-products, resulting from 
the catabolism of cytoplasm, and secondarily utilised for defence 
against animals. A few grams of an alkaloid constitute a protection 
not less efficient than the strongest spines. 
The diminution of the proportion of alkaloids in a given plant 
is often wrongly interpreted as a proof of their direct consumption 
as plastic material. But the decrease may be only apparent — for 
example, when, the alkaloids remaining unchanged, the amount 
of other substances becomes greater. Secondly, the fact that a body 
disappears from the plant does not demonstrate that it has been 
used as food : it may have been eliminated in a volatile state or 
otherwise transformed. Thirdly, it must not be forgotten that the 
percentage of nitrogen in alkaloids is generally very small, so that 
they would be a very poor nitrogen-store. Even in the case of 
caffein, which is exceptionally rich in nitrogen, numerous expe- 
riments of Clautriau, confirmed afterwards by Suzuki, lead to the 
conclusion that it is not a plastic substance. This. nevertheless, 
does not exclude the possibility of certain products of the splitting- 
up of the alkaloid molecule being ulteriorly resumed by anabolism, 
just as the essentially catabolic CO, formed in respiration can serve 
to regenerate starch in the green cell. 
