12 



The Use of a Simple Microscope. 



forming it. Altliough adulterations of food have been carefully 

 investigated, adulterations or admixtures in fabrics, whether of 

 animal or vegetable origin, have hitherto obtained but little 

 attention. A et, it is urged, the subject is an important one, and 

 well deserving systematic research. 



"All fibres employed for commercial purposes may be divided 

 into four classes, two of which are animal — i.e. wool and silk — 

 and two vegetable, which may be termed vascular."* 



The first representation is that of cotton (a), Fig. b.f The fibre 

 of cotton is a cellular hair, which may be recognised by its forming 

 a flat and slightly twisted band with apparently thickened edges. 

 " Very important investigations on this subject have been com- 

 menced in Manchester," and the question is asked " Are there 

 really any distinguishable microscopic differences between Sea 

 Island and Egyptian, New Orleans and African, or between 

 Brazilian and Surat ? " 



Wool (b) has a peculiar structure, readily to be distinguished 

 from all other animal and vegetable fibres, and differing slightly 



Fig. 5— a. Cotton, h. Wool. c. Silk. 



in its own varieties, as may be seen by reference to a paper on 

 " Hairs." :j: To this peculiar scaly structure that wool possesses so 



* Ilardwicke's 'Science Gossip,' No. I. vol. ii. p. 10, 'a Monthly IMedium of 

 Interchange and Gossip for Students and Lovers of Nature,' price 4d. This pub- 

 lication contains much varied and trustworthy information, that would prove 

 serviceable to the farmer. 



t To Dr. Forbes Watson we are indebted for the use of the blocks which illus- 

 trate this part of the subject. 



X ' Science Gossip,' vol. i. p. 29. 



