INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 749 



M. Bonnier made plants (hyacinths, tulips, &c.) artificially nectari- 

 ferous. Other experiments showed that the osmotic impetus of the 

 roots, and the capillary force of the vessels, are not necessary to, though 

 they accelerate, the emission of the saccharine liquid. 



In settled fine weather the quantity of nectar emitted is at a 

 minimum in the afternoon ; it is the same with the proportion of 

 water which it contains. In fact, the production of nectar is in direct 

 relation to the transpiration of the plant. 



The floral nectaries examined at different ages show that the 

 maximum production of nectar is at the epoch in which the ovary 

 finishes, and the fruit has not yet begun, its development. The pro- 

 portion of saccharose contained in the tissue varies in the same way, 

 whether emitted or not. There exists near to the saccharine tissues 

 an inverting ferment, which transforms the saccharose into glucose, 

 and abounds at the time when the fruit is about to develop. 

 Finally, the whole or greater part of the accumulated sugars return 

 to the plant ; the floral nectaries contribute to the nourishment of the 

 young fruit and the fertilized ovules, and the extra-floral nectaries to 

 that of the neighbouring organ about to develop ; at the same time 

 the saccharose diminishes relatively. 



Tlie nectariferous tissues, whether floral or extra-floral, lohether emit- 

 ting liquid or not, constitute special nutritive reserves, in direct relation 

 to the life of the plant. 



Causes of the Change in Form of Etiolated Plants.* — In 1873 

 Professor Godlewski published in 'Flora ' an account of his investiga- 

 tions respecting the formation of starch in chlorophyll-grains. In 

 that memoir he stated that the changes in form which plants undergo 

 in darkness are not due to the suspension of the assimilative process. 

 In 1875 and 1877, he published in the Polish language two short 

 notices of his further observations upon this subject, which he now 

 fully recounts in the present paper. 



Only the first series of his later experiments will be referred 

 to now, namely, those bearing upon the question as to the relation 

 of the assimilative process to the change of form in growing j^lants 

 deprived of light. It is a general rule, to which there are some 

 exceptions, that internodes grown in the dark are longer, and leaves 

 are smaller, than those which develop in sunlight. In Prings- 

 heim's ' Jahrbuch f. wiss. Botanik,' vol. vii. p. 213, Dr. G. Kraus 

 has sought to explain the latter fact by the hypothesis that it is chiefly 

 out of assimilated matter freshly formed in growing green leaves 

 themselves that they expand to their full size, and hence the diminutive 

 size of etiolated leaves is thought by him to be directly dependent 

 upon the absence of the assimilative process. 



In Professor Godlewski's experiments germinating plants were 

 cultivated in an atmosphere deprived of its carbonic acid, some of them 

 in light, others in perfect darkness, but under similar conditions of 

 temperature and moisture. It was found tliat when the plants had 

 exhausted the food stored in the seed and had ceased to grow, the total 



* ' I3ot. Zeit.,' xxxvii. (1879) p. 81. 



