664 SUMMARY OF CURRENT RESEARCH KS RELATING TO 



(2) Preparing Objects- 

 Studying Structure and Life-history of Crithidia melophagia.* 

 Annie Porter examined numerous specimens of Melophagus ovinus, in 

 which she found the Flagellate parasite Crithidia melopJiat/ia. The host, 

 known as the " ked," belongs to the Diptera (Hippoboscidae), posses- 

 sing extremely reduced wings ; the keds were obtained from English 

 southern counties. For observations on the living organism two methods 

 of procedure were followed. The alimentary canal was isolated and 

 divided into separate portions ; these were either teased out with needles 

 and examined in saline, or the contents were squeezed out and also 

 examined in saline. Alkaline methylen-blue and neutral-red were occa- 

 sionally used as intra-vitam stains. 



For fresh preparations used in work on hereditary infection, the 

 ovaries and gnt were dissected out and mounted in saline. The be- 

 haviour of the Crithidia and the manner in which they passed out of the 

 gut were carefully watched. In investigations of the stages of C. melo- 

 phagia in the egg and puparia, smear preparations were found to be pre- 

 ferable to sections. The method adopted was to prick the egg or open 

 the young puparian and express the contents on to a slide. The contents 

 were at once fixed, then allowed to flow over the slide ; this procedure 

 obviated distortion and rupture of the parasites. As these preparations 

 contained much fatty matter, the slides were treated with ether, and after 

 washing with absolute alcohol were stained and mounted in the usual 

 manner. 



For making permanent preparations the alimentary tract of the 

 Dipteran host was removed and divided into portions, which usually were 

 teased and fixed wet. The vapour of formalin or of osmic acid was 

 mostly used for fixation, but sublimate-acetic-alcohol and Bouin's fluid 

 were also employed. The stains used were Giemsa, thionin, iron- 

 ic aeinatoxylin, and gentian-violet with Delafield's hasmatoxylin ; the last 

 was particularly useful for the membrane and flagella. Preparations 

 mounted in neutral Canada balsam were superior to dry films or to films 

 mounted in any other manner. 



Demonstrating Muscle-spindles.t — P. A. Cilimbaris investigated 

 the muscles of the human eye chiefly, and also those of lower animals ; 

 in the latter case the results were for the most part negative. Frozen 

 sections of fresh muscle were overstained with haemalurn and differen- 

 tiated with hydrochloric-acid-alcohol, washed in tap-water, and mounted 

 either in laavulose syrup or in balsam. This method was excellent for 

 the sarcoplasm and the interstitial substance ; the contractile elements, 

 however, were unstained. 



The fixative used was 10 p.c. formalin, and frozen sections only were 

 used. 



Maceration preparations were made by Sihler's method : the muscles 

 were placed in a mixture of 1 vol. acetic acid, 1 vol. glycerin and 6 vol. 

 1 p.c. aqueous solution chloral hydrate, then for weeks to months in a 

 mixture of 1 vol. Ehrlich's haematoxyfin, 1 vol. glycerin and 6 vol. 



* Quart. Journ. Micr. Sci., lv. (1910) pp. 189-224 (2 pis. arid 15 text figs.), 

 t Arch. Mikroskop. Anat. u EntwickL, lxxv. (1910). 



