no intrusions or replenishments from the mainland, for the egg-type at least would 

 have "gone to pieces" under the impact of such a strain. 



We have denied that there exists upon the mainland, in the case of the California 

 Jay, any recognizable evidence of correlation between variation of eggs and somatic 

 changes in the parents. But that is not to say that such evidence may not exist. For 

 we have already conceded that such evidence of correlation, or at least of concomitant 

 variation, might become instantly manifest under selective breeding. The somatic 

 uniformity of the mainland jay may still represent potential variations now held in 

 stern check by interbreeding. The case of the Santa Cruz Island Jay may represent 

 an accidental release of a tendency toward increase in size, latent but held in leash, in 

 the case of its particular ancestors. This being true, or at least possible, we are not 

 free to ascribe all the evidence of change in A. insularis to the slow workings of 

 environmental reaction alone. If we are correct in our surmise that insularis is the 

 product of a single pair of birds accidentally or artificially isolated from mainland stock, 

 the distinctions which we observe might have arisen immediately, or within a few 

 hundred years at most. While we do not know even yet what all the geno-dynamic 

 values of the Santa Cruz Island Jay are, we have greatly restricted the field of discus- 

 sion, and we regard this inquiry as a fair example of the methods and promises of 

 comparative oology. 



SIMPLE INSTRUCTIONS FOR THE COLLECTING AND PRESERVATION 



OF BIRDS' EGGS. 



Not all bird-lovers are egg-collectors, but many who lack experience would be 

 glad to retrieve an occasional rarity, in the name of science, it they knew how to 

 proceed. The tollowing suggestions are not meant to be exhaustive, nor are they 

 addressed to "old hands," whether protessional or amateur. 



The basis ot all modern egg collecting is the set, or clutch, which comprises the 

 nestrul, or all the eggs which a bird would normally lay for one sitting. Any number 

 less than this is of little or no value, save in the case of extreme rarities. 



A set of eggs is of little or no value to science unless it is well collected; that is, 

 that its collecting conforms substantially to the following requirements: 



First, that it be well identified. The eggs must not be touched until the collector is 

 thoroughly satisfied as to the identity of the parent bird, or has secured it. 



Second, that the eggs be removed and transported to the work-room under such 

 circumstances, or accompanied by such marks ot identification, that there can be no 

 possible doubt as to which eggs belong together in one individual set. 



Third, that the eggs be well prepared. The contents should be entirely removed 

 through a single, small, round hole drilled midway on one side (the least showy side), 

 and the inside of the shell thoroughly rinsed with clean water, and dried. Small, 

 inexpensive drills, carefully graded as to size and use, may be obtained of any supply 

 house, or in default of such, a wire nail of suitable size, perfectly straight, may be 

 ground or filed to a perfectly rounded taper point, and finished off with a fine file held 

 with the grain. The final furrowed surface of lengthwise grooves, which the drill 

 requires, can be obtained only by pressing the taper point firmly between the file 

 groove until the minute rugosities of the file ridges imbed themselves in the softer 

 steel. These home-made drills are incomparable, and almost obligatory for delicate 

 eggs. The contents of the egg are forced out by a jet of air played through a blow- 

 pipe, held very close to the hole but not in contact with it. Eggs advanced in incuba- 

 tion may require the patient use of delicate instruments, especially an embryo hook 

 and slender-tipped forceps, or, if time allows, the use of digestive fluids, compounds of 

 pepsin, or, in default of these, a saturated solution of cooking soda applied over night. 



In case of common eggs, near the hatching point, but necessary for use in series, 

 if time fails, a rougher method may be employed. A rounded hole substantially half 

 the shorter diameter of the egg may be broken out by the skillful use of curve-tipped 

 forceps, and the embryo lifted out. This is contrary to all the books and very unpro- 

 fessional, but we do it under the spur of necessity rather than lose a coveted link in 

 a series. 



Attention should be paid to the drainage of the egg, after it has been twice rinsed 

 by water injected, shaken thoroughly, and blown out. The egg should be rested hole 

 down for a few hours on a blotter, or better, an absorbent linen cloth. If, upon exami- 

 nation, it is still "drizzling," apply the blow-pipe for a last toot. When thoroughly 

 drained, turn hole up to dry. Be careful not to leave imperfectly blown eggs long- 

 enough to get glued to the drain cloth; but if you are caught, remove the egg only by 

 patient application of water on the opposite side of the cloth. 



Fourth, that the eggs be well marked. Use the softest pencil obtainable, a "6B" 

 if possible. Use your own system or follow our suggestions (recorded beyond), but 

 don't leave unmarked eggs around. 



__ . Page twenty-nine 



