M. C. COOKE ON BLACK MOULDS. 271 



of others will follow the knowledge that a special field of work has 

 been entered upon. Satisfaction will result from the self-conscious- 

 ness that sound and nut superficial knowledge is being acquired. 

 Respect for his work's sake, and deference to his opinion, are sure 

 rewards to be anticipated, and ultimately, not only must such an one 

 be in a position to contribute to the advancement of science, to 

 become an honour to the club of which he is a member, but every- 

 where to meet with the encouragement which the best and highest 

 authorities of the age will freely extend to an honest and thorough 

 worker in any definite department. 



Returning from this digression to the mode by which the col- 

 lected specimens of black moulds are to be turned to advantage, I 

 would suggest that a casual glance through a number of these will 

 at once suggest their points of agreement and divergence, and hence 

 the bases of their systematic classification. All are possessed of 

 threads, and naked spores, but these differ, and their differences 

 assist in the grouping together of allied forms into genera. Some 

 threads have their spores borne at the base, others at the apices, 

 others at the sides. Some have simple spores, others multiseptate. 

 Then by a comparison of the figures and descriptions in the Hand- 

 book of British Fungi, a knowledge may be obtained of the charac- 

 teristics of the principal genera. Next, the differences which sub- 

 sist between very similar forms, those which are termed specific 

 differences, and so commencing by giving a recognised name to dis- 

 tinguish one from another. Having thus laid the foundation for 

 work, each or any of the individual forms may form the subject of 

 investigation. For instance, how does it grow, what the conditions 

 of its life, through what stages do the spores pass, how do they 

 germinate, how does the plant reproduce itself, how may it be cul- 

 tivated, what is its relationship to other forms — all these are direc- 

 tions in which investigation may legitimately proceed, and as little 

 or nothing is known, is sure to produce results which others will be 

 glad to learn. That which is applicable to these organisms, is also 

 applicable to very many others. It matters little whether we call 

 them white moulds, black moulds, Desmids, Conferva?, Acari, 

 Podurae — a similar course is available for all. 



There is one other point to which no allusion has yet been made, 

 viz., the drawing and measurement of microscopical objects. Trust- 

 worthy drawings made to a definite scale, are always valuable, and 

 will be when names of genera and species become anticpaated, and 



