TARASITIC PROTOZOA F(JUXI) li\ SOUTH AFRICA. I9I 



Blcpharocorys iincinata has been observed in the caecum of 

 a horse, and Isotricha was present in the rumen and reticulum of 

 u bull, both from the Pretoria district. 



Spiroch.et.e. — Spirochetes have been found in three pis- 

 cine hosts, namely. RJiinohatns colnuuuc (= R. annulatus), a 

 sandshark ; Pagcllits Jiionnynis, the zee basje; and Dente.r argy- 

 rozona, the silver fish, all from False Bay. Heavy infections 

 were not encountered. 



The spirochaete from the blood of RJiinuhatus colunuuc, as I 

 reported last year, is small and has somewhat acuminate ends. 

 It shows a diffuse nucleus of chromatin orranules. A trace of a 

 membrane or crest was seen in a few specimens. The organism 

 measures from 11.3^1 to 24.6^ long- by o.6/a to 1.3^1 broad. The 

 short forms are approximately half the length of the long forms, 

 probably due to transverse division of the organism. 



The zee basje, PagcUus mormyrus, was found to contain a 

 spirochete in its stomach. This spirochete varies in length from 

 I2/X to 28.6/1,, and has a breadth of i/u,. It has a diffuse nucleus 

 of chromatin granules, and some show a tightly contracted merii- 

 brane or crest. 



Examination of scrapings of the gills of the silverfish, Dentex 

 argyro::ona, showed the presence of a spirochete. The dimen- 

 sions of the organism are from i6/^ to 34.6/A long, wnth a breadth 

 of ifx.. Multiplication by fission was observed in life. 



DIFFRACTION-PHENOMENA IN FILMS OF BLOOD 



CELLS AND IN SURFACE-CULTURES OF 



MICRO-ORGANISMS. 



By A. PijPER, M.D., L.S.A. 



{Abstract.) 



Read July 11, 1919. 



The author, with the aid of lantern slides, gave a brief 

 synopsis of the physical principles of diffraction and interference, 

 and explained how films of red blood cells and of more or less 

 spherical micro-organisms could be regarded as " diffraction- 

 gratings." An apparatus was demonstrated by means of which 

 a powerful beam of parallel light-rays could be projected on such 

 " natural diffraction-gratings," and the resulting diffraction- 

 phenomena were made visible on the receiving screen of the 

 apparatus. 



