( 859 ) 

 SUMMARY 



OF CDRBENT RESEARCHES RELATING TO 



ZOOLOaY AND BOTANY 



{principally Invertehrata and Cryptogamia), 



MICROSCOPY, &c., 



INCLUDING OEIGENAL COMMUNICATIONS FROM FELLOWS AND OTHERS* 



ZOOLOGY. 



A. GENEHAL, including' Embryology and Histology 

 of the Vertebrata. 



Physiology of Protoplasmic Movement.^ — A. G. Bourne has 

 done considerable service to English biologists by translating Prof. 

 Engelmann's important essay on the physiology of protoiilasmic 

 movement. Like muscular and ciliary movements, those of living 

 protoplasm are to be regarded as phenomena of contractility. Their 

 special character is " that the jjarticles of the contractile mass move, 

 as a rule, not in relation to any fixed position of equilibrium, but can 

 change their arrangement and position (and this apparently volun- 

 tarily) as do the moving particles of a fluid substance. Further, 

 the impulse to such movements does not normally come from without, 

 but originates in the moving particles themselves." Protoplasm thus 

 possesses, not only contractility and irritability, but also automatism. 



Protoplasm may be doubly refractive, and different parts of a 

 single mass may have different refractive powers. It varies in the 

 degree of its fluidity, has great cohesive and great extensile powers, 

 and has a tendency to form droplets ; but these properties vary con- 

 siderably. So again the contained granules vary in number, and, 

 while most are albuminous, some are fatty and others inorganic. 

 There is no chemical distinction between contractile and non-con- 

 tractile protoplasm. 



In the movements of naked protoplasm three chief types are to 

 be distinguished — amoeboid, streaming, and gliding. The first may 

 be very well studied in the plasmodium of Myxomycetes, where the 

 masses are large and the movements extremely rapid. When the 



• The Society are not to be considered responsible for tbe views of the 

 authors of tbe papers referred to, nor for the manner in wliich those views 

 may be expressed, the main object of this part of tlie Jourtial bcin"; to present a 

 summary of the pafjers as actually pnhlKhed, so as to provide tlie Fellows with 

 a guide to the additions made from time to time to the Library. Objections and 

 correctiouB should therefore, for the most part, be addressed 1o the authors. 

 (The Society are not intended to be dc^noted by tlie editorisil " we.") 



t Quart. Joiirn. Micr. Sci., xxiv. (1884) pp. 370-418. 



3 L 2 



