﻿FIELD AND FOREST. 83 



consisted of boiling the fibre of blood in caustic potash, with the 

 evident intention, as any one skilled in the rudiments of chemistry 

 would suppose, of destroying all animal matter, as we generally under- 

 stand those terms; but if cellulose is present in the mass of the sub- 

 stance it will not be destroyed by treatment of this kind. The strength 

 of potash solution used consists of about four ounces of water to about 

 one of caustic potash. When the nitrogenous structure is supposed to 

 be destroyed, including blood corpuscles, and the mass is rendered homo- 

 genous, I test for cellulose. I deem it reasonable to say that any one 

 accustomed to the use of the high powers of the microscope would soon 

 abandon his investigations in search of blood-globules in such homo- 

 geneous matter, but by the means I suggest every portion of cellu- 

 lose present will spring into view, and will expand under the treatment 

 twenty fold. I now believe this method is somewhat objectionable 

 from the liability of foreign substances coming in contact with the mat- 

 ter under investigation, the potash might be even contaminated by 

 the woody and cotton fibers. I now prefer operating on blood di- 

 rectly with muriatic and sulphuric acids, and tincture of iodine, as 

 previously described. 



When we desire to see the microscopic structure of a plant-leaf we 

 render it transparent, and, by a system of staining, its mechanical di- 

 visions are more clearly defined; but if the object of the investigation is 

 to discover the relative amount of amylaceous cellulose present, micro- 

 chemistry takes a very different course. The leaf may be boiled in 

 caustic potash to remove all soluble matters consisting of starch, 

 &c. The potash should next be removed by distilled water and other 

 means. If the remaining mass of cellulose is submitted to the acids 

 and iodine test, the easily digestable cellulose will be converted into a 

 blue mass, but the vascular bundles of the leaf will retain their perfect 

 structures and would prove, if used as food by animals, very indigesti- 

 ble, as such cellulose structures resist fermentation for years. Many of 

 the grasses are largely composed of this woody structure and are there- 

 fore better fitted for the manufacture of textile fabrics than for the 

 feeding of cattle; but should the microscope reveal that the larger pro- 

 portion of cellulose is converted into a blue mass, we conclude that the 

 grass will excel as a fat-former. The illustrations represent some of the 

 out-cropping of micro-chemical investigations in cellulose, as relates 

 directly to agriculture. 



