SCIENTIFIC AND APPLIED 

 PHARMACOGNOSY 



THALLOPHYTES 



The Thallophytes, while of very great botanical interest, com- 

 prise about 100,000 species, yet relatively few are of any economic 

 importance. The Alga? are chiefly used because of the mucilage that 

 they contain and as a source of iodin. A number of lichens con- 

 tain important coloring matters. A few of the fungi are used in 

 medicine, although a great number of them contain exceedingly toxic 



principles. 



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SCHIZOMYCETES OR BACTERIA 



Bacteria and their products are extensively used in medicine, as 

 well as in the industries. The preparations, known as serums and 

 vaccines are employed as specific cures for certain diseases, and are 

 especially valuable in prophylaxis and diagnosis. Their manufac- 

 ture requires great skill and special facilities are necessary to produce 

 them. Furthermore, they can be manufactured only under govern- 

 ment license and inspection. While there are many biological prod- 

 ucts used in diagnosis, prevention and treatment, which cannot prop- 

 erly be placed under any definite classification, yet for the greater 

 part these products may be grouped under two chief classes, vaccines 

 and antiserums. 



Vaccines are essentially weakened or modified viruses. The 

 general action of vaccines is therefore preventive or prophylac- 

 tic and not curative. There are several methods which may be 

 employed in modifying or attentuating viruses. The processes 

 involve the treatment of viruses in such ways that they may be 

 injected into the animal body without danger of producing serious 

 pathologic conditions, while at the same time sufficient specific 

 infectious qualities must be present to produce mild reactions. The 



