SCIENCE-GOSSIP. 



237 



Crystallizations of Fats. — Recent investiga- 

 tions demonstrate that the crystalline forms of 

 animal and vegetable fats differ materially. To 

 illustrate this in some degree, we now submit three 

 illustrations, chaulmugra fat crystals, crystals of 

 human fat, and the fat crystals of a monkey. 

 To obtain crystals of the fatty glycerides of 

 animal fats, the melted fat should cool gradually 

 for about ten hours in a temperature of about 

 sixty-rive degrees Fah., in order to get the fully- 

 developed crystallization. The fat of plants will 

 crystallize within as 

 many minutes. In 

 a paper on this sub- 

 ject by Mr. T. Tay- 

 lor, and which was 

 published by the 

 Division of Micro- 

 scopy of the United 

 States Agricultural 

 Department, he de- 

 tails the methods 

 that he adopted in 

 his researches in this 

 direction. For the 

 purpose of securing 

 interesting and beau- 

 tiful groupings of the 

 crystals of seed fats 

 it is necessary to 

 follow strictly the 

 method outlined, 

 otherwise many of 

 the most beautiful 

 forms will not be 

 obtained. Briefly de- 

 scribed, the method 

 is as follows : In 

 preparing chaulmu- 

 gra fat (extracted 

 from the seeds of 



Chaulmugra Fat Crystals. 



Clearing of Vegetable Microscopical Sec- 

 tions. — One of the most troublesome processes 

 connected with the staining and mounting of vege- 

 table tissues is the preliminary clearing. In the 

 " Pharmaceutical Journal " Mr. W. Kirby, F.L.S., 

 describes a method of clearing which is at once 

 practical and effective. Clearing agents are of two 

 kinds, namely, those which act by virtue of their 

 property of strongly refracting light, and those 

 which disintegrate and dissolve the obtrusive cell- 

 contents. To the first class belong clove oil, cedar- 

 wood oil, cajuput oil, 

 xyol, dammar resin, 

 Canada - balsam, 

 glycerine, and other 

 similar bodies; to the 

 second class, solu- 

 tions of caustic 

 potash, eau de Jav- 

 elle, eau de Labar- 

 aque, phenol, chloral 

 hydrate, etc. The 

 usefulness of most of 

 these substances is 

 comparatively limi- 

 ted, while some of 

 them are decidedly 

 objectionable for per- 

 manent m ounts, 

 because of their ener- 

 getic action upon the 

 tissues. An efficient 

 clearing method 

 should ensure the 

 removal of the cell 

 contents, but should 

 have a minimum 

 effect upon the cell- 

 walls. Without dis- 

 cussing the merits of 

 each of the usual 



Fat Crysuti. 



Pal ' 1 1 1. 'i'. -1 donkey, 



1 



Cyntxardui • put a 



small : I it on a microscopical 



placing > h ai i-, used In 



general mounting I: 



lamp until the fit melts— do not overheat rind 

 allow It I ri a temperature of nixty di 



Jah Within a few mlnotes the mount will a 

 white, owing to tlv cation of the (al The 



slide Is now ready for observation under the 

 mi'.r'/v.'.jy 



methods adopted for clearing, I may say that 

 in my hand, the process I use more nearly 



fulfils the above conditions than any other 1 

 bave ti led, the 1 1 1 tlonj nftet treatment bi Ing 

 obtained In a condition suitable for putting up in 



!•• Utui'.iu, or resinous mountains. I'i.ue 

 the Sections in a fresh, clear solution of chlorinated 



lime, and allow ihem to rei mil quite I ilea, lied, 



nay, from two to four 01 live minutes; gently warm 

 in a tesl t"l" (or a few second'., then quickly 



