16 



SCIENCE. 



[N. S. Vol. VII. No. 158, 



tion is absent have greatly reduced num- 

 bers of stomata, as in the dodders (Cuscuta) 

 and the little mistletoes (Eazoumofskya), 

 while they are present in abundance in 

 green parasites (Viscum and Phoraden- 

 dron). 



From the foregoing rapid and quite sum- 

 mary survey of the different phases of this 

 question we are warranted in concluding : 



1. That one of the functions of stomata 

 is the admission of carbon dioxide to the 

 chlorophyll-bearing tissues of the plant, for 

 use in the formation of the carbohydrates. 



2. That the loss of water by terrestrial 

 plants was originally hurtful, and is so now 

 in many cases. 



3. That if plants have utilized this con- 

 stant phenomenon it is for the supply of 

 food matters of secondary importance, as 

 the salts in solution in the water of the 

 soil. 



Charles E. Bessey. 

 The University of Nebraska. 



EECENT PB0GBE8S IN AGBICULTUBAL 



CHEanSTBY* 



I. 



Since the last resume of progress in agri- 

 cultural chemistry was reported to this 

 body a considerable advance has been made 

 in our knowledge of the methods and 

 means of nitrogen assimilation. The most 

 marked progress has been made along the 

 line of the inoculation of seed and the soil 

 with nitrifying ferments. Much has been 

 done in this direction, and the results of the 

 experiments are sufficiently encouraging to 

 warrant the belief that much good may yet 

 come to agriculture by following out this 

 line of investigation. In 1895, in the Year- 

 book of the Department of Agriculture, the 

 following statements occur : 



* Prepared at the request of the ofScers of Section 

 C, of the A. A. A. S., and read before Section C and 

 the American Chemical Society at the Detroit meet- 

 ing, August, 1897. 



" It may not be long until the farmer 

 may apply to the laboratory for particular 

 nitrifying ferments to be applied to such 

 special purposes as are mentioned above. 

 Because of the extreme minuteness of these 

 organisms the too practical agronomist may 

 laugh at the idea of producing fertility 

 thereby, and this idea, indeed, would be of 

 no value were it not for the wonderful 

 facility of propagation which an organism 

 of this kind has when exposed in a favora- 

 ble environment. It is true that the pure 

 cultures which the laboratory affords would 

 be of little avail if limited to their own ac- 

 tivity, and it is alone in the possibility of 

 their almost illimitable development that 

 their fertilizing effects may be secured." 



It cannot be said that the prophecies- 

 foreshadowed in the above quotation have 

 been fully verified, but at least something 

 has been accomplished. 



From the time that it was demonstrated 

 by Hellriegel and Wilfarth that the power 

 which leguminous plants possess of increas- 

 ing their stores of nitrogen was due to the 

 bacteria inhabiting nodules on their root- 

 lets, the study of this phenomenon has been 

 pushed with great vigor in all parts of 

 the world. Intimately related, as it is, to 

 the nitrifying organisms of the soil, it has,, 

 nevertheless, been demonstrated that the- 

 two species of bacteria, the general nitrify- 

 ing species and the special so-called sym- 

 biotic species, inhabiting the roots of plants,, 

 are entirely diiferent in their nature, and 

 that their activity is not mutually converti- 

 ble. 



The most extensive experiments in the- 

 direct inoculation of the soil with nitrify- 

 ing ferments have been conducted by Dr. 

 Salfeld, of Lingen, in Hanover. The 

 greater part of the experiments has been 

 made on peaty soils, as it is in such soils 

 that the greatest deficiency of nitrifying 

 organisms is observed. Au excellent re- 

 view of Dr. Salfeld 's work has been pub- 



