M 



CINENCHTMA, OR LACTIFEROUS TISSUE. 29 



ceiving the design of nature in giving to this tube the tbrm 

 she has. It is the only kind fitted to convey nourishment, and 

 <;ive support to tlio tondercst shoot as it protrudes to light. — 

 if a common cylindrical tube were used, tlie great llcxures 

 made by such tender parts, under the influence of wind and 

 rain, would be very liable to crush the tube on one side or tear 

 it asunder on the other, as it is well known that a tube cannot 

 be bent without injury, and it is ccpially well known that a 

 coil may be bent in any direction, and return to its first po- 

 sition uninjured. Here nature in her wisdom, has adapted 

 organs to the necessity of the case, and she only uses this 

 kind where the above circumstances seem to demand it, as 

 they are never tbund in any circumstances where they are not 

 terminated with the organ. 



32. The varieties of this tissue as exhibited by the micro, 

 scope are numerous, l)ut we shall notice only a single kind of 

 its variations. Annular ducts, as they are called, are tubes in 



b a which the spires are apparently broken into 



^^ lings and joined at their extremities. Some- 

 times the rings lie in regular order and in con- 

 tact with each other, having the appearance 

 of tiic true spiral vessel, as seen in lig. 14, a. 

 At another time the rings appear separated 

 and irregular, and are detached from the tube 

 and King lengthwise in it, as seen in fig. 14, b. 

 These appearances may be seen in the stem of 

 the Imjjatiens, and other forms will be readily 

 detected in the same plant. We deem it inex- 

 pedient to occupy space in describing varieties 



of vegetable tissue, which are reducible, by the least sagacity, 



to a primitive form. 



Section 5. — Cincnchyma, or Lactiferous Tissue, 



33. Cinenchyma is a class of tissue but recently demon- 

 Btrated by Professor Schultz. It consists of minute tubes 

 anastimosing with each other, and arranged in no definite 

 direction, in reference to the other tissues. The tubes are 

 of very difierent diameter in different parts. The vessels 

 generally take a waving direction, seldom proceeding in a 

 straight line. The tubes become thickened in age by the 

 deposition of new matter. Tlie Cinenchyma is found in 

 greatest abundance in the liber of the bark, across the pa- 

 renchyma of the leaves ; .but, no doubt, exists in almost 

 every part of Flewering plants. It has been detected in 



3* 



