1896 THE MICROSCOPE. 59 



The Prothallium of a Fern. — It is very interesting to view 

 a prothallium of a fern. They may be found at the base of 

 the plants and may be esily obtained in a green-house where 

 ferns are cultivated. They are small, heart-shaped bodies and 

 are interesting as they contain the archegonia and antheridia 

 which will eventually produce a new fern. The antheridia 

 project from the basal portion of the under surface of the pro- 

 thalium. One of the interior cells becomes divided into sperm- 

 cells, in each of which is a specially coiled spermatozoid. The 

 archegonia are cellular projections from the anterior portion of 

 the under surface of the iirothallium. These protluillia may 

 be dried and mounted in balsam. 



Eosin Staining. — Dilute solutions of eosin, one part to one 

 thousand of water, may be used for animal tissues. The dif- 

 ferent jDarts are differentiated by different tints. Sections are 

 stained in a minute and a half. Then wash It in waier acidu- 

 lated slightly with acetic acid, and examine in glycerine ; or, 

 mount in balsam after the water is removed and the section is 

 thoroughly dried. 



Identification of Lichens by Measuring Spores. — Many 

 species of lichens are outwardly very similar but may be inden- 

 tified by the difference in the size of their spores. Nearly all 

 works on lichens give the sizes of the largest and smallest 

 spores. The identification may be determined by a measure- 

 ment of the spores. This is not difficult. The microscoj^e 

 should be provided with an eye-piece micrometer. Then let 

 a stage-micrometer, divided by thousandths of a millimetre, be 

 placed on the stage of the instrument and let the observer note 

 how many of its divisions are erjual to one division of the eye- 

 piece micrometer. By this method the spores can subsequently 

 be measured by the use of the eye-piece micrometer. 



Microscopical Examination of Sputum for January. — 

 Number of examinations made in the Battle Creek iSauitarium, 

 36; number of cases, 29; number of specimens in which tuber- 

 cule bacilli were found, ]-i. 



Patients whose spntum contained tubercular germs, were 

 received from the following states; Michigan, 9; Texas, 1; 

 Colorado 1; Iowa, 1; Mississippi, 1; Ontario, 1. Total. 14. 



